1.
Cactus
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A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek κάκτος, kaktos, Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought, many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on earth. Cacti show many adaptations to conserve water, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, as well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of leaves, enlarged stems carry out photosynthesis, Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka. Cactus spines are produced from specialized structures called areoles, a kind of highly reduced branch, areoles are an identifying feature of cacti. As well as spines, areoles give rise to flowers, which are usually tubular, Cactus stems are often ribbed or fluted, which allows them to expand and contract easily for quick water absorption after rain, followed by long drought periods. Like other succulent plants, most cacti employ a mechanism called crassulacean acid metabolism as part of photosynthesis. Transpiration, during which carbon enters the plant and water escapes, does not take place during the day at the same time as photosynthesis. The plant stores the carbon dioxide it takes in as malic acid, retaining it until daylight returns, because transpiration takes place during the cooler, more humid night hours, water loss is significantly reduced. Many smaller cacti have globe-shaped stems, combining the highest possible volume for water storage, the tallest free-standing cactus is Pachycereus pringlei, with a maximum recorded height of 19.2 m, and the smallest is Blossfeldia liliputiana, only about 1 cm in diameter at maturity. A fully grown saguaro is said to be able to absorb as much as 200 U. S. gallons of water during a rainstorm, a few species differ significantly in appearance from most of the family. At least superficially, plants of the genus Pereskia resemble other trees and they have persistent leaves, and when older, bark-covered stems. Their areoles identify them as cacti, and in spite of their appearance, they, Pereskia is considered close to the ancestral species from which all cacti evolved. In tropical regions, other cacti grow as forest climbers and epiphytes and their stems are typically flattened, almost leaf-like in appearance, with fewer or even no spines, such as the well-known Christmas cactus or Thanksgiving cactus. Cacti have a variety of uses, many species are used as ornamental plants, others are grown for fodder or forage, cochineal is the product of an insect that lives on some cacti
2.
Aloe
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Aloe, also written Aloë, is a genus containing over 500 species of flowering succulent plants. The most widely known species is Aloe vera, or true aloe, other species, such as Aloe ferox, also are cultivated or harvested from the wild for similar applications. The APG IV system places the genus in the family Asphodelaceae, in the past, it has been assigned to the family Aloaceae or to a broadly circumscribed family Liliaceae. The plant Agave americana, which is sometimes called American aloe, belongs to the Asparagaceae, the genus is native to tropical and southern Africa, Madagascar, Jordan, the Arabian Peninsula, and various islands in the Indian Ocean. A few species have become naturalized in other regions. Most Aloe species have a rosette of large, thick, fleshy leaves, Aloe flowers are tubular, frequently yellow, orange, pink, or red, and are borne, densely clustered and pendant, at the apex of simple or branched, leafless stems. Many species of Aloe appear to be stemless, with the rosette growing directly at ground level and they vary in color from grey to bright-green and are sometimes striped or mottled. Some aloes native to South Africa are tree-like, the APG IV system places the genus in the family Asphodelaceae, subfamily Asphodeloideae. In the past it has also assigned to the families Liliaceae and Aloeaceae, as well as the family Asphodelaceae sensu stricto. The circumscription of the genus has varied widely, many genera, such as Lomatophyllum, have been brought into synonymy. Species at one time placed in Aloe, such as Agave americana, have moved to other genera. Over 500 species are accepted in the genus Aloe, plus even more synonyms and unresolved species, subspecies, varieties, Aloe species are frequently cultivated as ornamental plants both in gardens and in pots. Many aloe species are highly decorative and are valued by collectors of succulents, Aloe vera is used both internally and externally on humans, and is claimed to have some medicinal effects, which have been supported by scientific and medical research. They can also be made into types of special soaps, historical use of various aloe species is well documented. Documentation of the effectiveness is available, although relatively limited. Of the 500+ species, only a few were used traditionally as herbal medicines, also included are A. perryi and A. ferox. The Ancient Greeks and Romans used Aloe vera to treat wounds, in the Middle Ages, the yellowish liquid found inside the leaves was favored as a purgative. Unprocessed aloe that contains aloin is generally used as a laxative, some species, particularly Aloe vera, are used in alternative medicine and first aid
3.
Botany
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Botany, also called plant science, plant biology or phytology, is the science of plant life and a branch of biology. A botanist or plant scientist is a scientist who specialises in this field, the term botany comes from the Ancient Greek word βοτάνη meaning pasture, grass, or fodder, βοτάνη is in turn derived from βόσκειν, to feed or to graze. Nowadays, botanists study approximately 410,000 species of plants of which some 391,000 species are vascular plants. Medieval physic gardens, often attached to monasteries, contained plants of medical importance and they were forerunners of the first botanical gardens attached to universities, founded from the 1540s onwards. One of the earliest was the Padua botanical garden and these gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomy, in the last two decades of the 20th century, botanists exploited the techniques of molecular genetic analysis, including genomics and proteomics and DNA sequences to classify plants more accurately. Modern botany is a broad, multidisciplinary subject with inputs from most other areas of science, dominant themes in 21st century plant science are molecular genetics and epigenetics, which are the mechanisms and control of gene expression during differentiation of plant cells and tissues. Botany originated as herbalism, the study and use of plants for their medicinal properties, many records of the Holocene period date early botanical knowledge as far back as 10,000 years ago. This early unrecorded knowledge of plants was discovered in ancient sites of human occupation within Tennessee, the early recorded history of botany includes many ancient writings and plant classifications. Examples of early works have been found in ancient texts from India dating back to before 1100 BC, in archaic Avestan writings. His major works, Enquiry into Plants and On the Causes of Plants, constitute the most important contributions to science until the Middle Ages. De Materia Medica was widely read for more than 1,500 years, important contributions from the medieval Muslim world include Ibn Wahshiyyas Nabatean Agriculture, Abū Ḥanīfa Dīnawarīs the Book of Plants, and Ibn Bassals The Classification of Soils. In the early 13th century, Abu al-Abbas al-Nabati, and Ibn al-Baitar wrote on botany in a systematic and scientific manner and these gardens continued the practical value of earlier physic gardens, often associated with monasteries, in which plants were cultivated for medical use. They supported the growth of botany as an academic subject, lectures were given about the plants grown in the gardens and their medical uses demonstrated. Botanical gardens came much later to northern Europe, the first in England was the University of Oxford Botanic Garden in 1621, throughout this period, botany remained firmly subordinate to medicine. German physician Leonhart Fuchs was one of the three German fathers of botany, along with theologian Otto Brunfels and physician Hieronymus Bock, Fuchs and Brunfels broke away from the tradition of copying earlier works to make original observations of their own. Bock created his own system of plant classification, physician Valerius Cordus authored a botanically and pharmacologically important herbal Historia Plantarum in 1544 and a pharmacopoeia of lasting importance, the Dispensatorium in 1546. Naturalist Conrad von Gesner and herbalist John Gerard published herbals covering the medicinal uses of plants, naturalist Ulisse Aldrovandi was considered the father of natural history, which included the study of plants
4.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
5.
Arid
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A region is arid when it is characterized by a severe lack of available water, to the extent of hindering or preventing the growth and development of plant and animal life. Environments subject to arid climates tend to lack vegetation and are called xeric or desertic, most arid climates surround the equator, these places include most of Africa and parts of South America, Central America and Australia. The distribution of aridity observed at any one point in time is largely the result of the circulation of the atmosphere. The latter does change significantly over time through climate change, for example, temperature increase across the Nile Basin over the next 30–40 years could change the region from semi-arid to arid, resulting in a significant reduction in agricultural land. In addition, changes in use can result in greater demands on soil water. Durrenberger, R. W. Arid Climates, article in The Encyclopedia of Climatology, p. 92-101, Edited by J. E. Oliver and R. W. Fairbridge, Van Nostrand Reinhold Company, New York, ISBN 0-87933-009-0. J Aridity Indexes, article in The Encyclopedia of Climatology, p. 102-107, Edited by J. E. Oliver and R. W. Fairbridge, Van Nostrand Reinhold Company, New York, blue Peace for the Nile Report,2009, Strategic Foresight Group
6.
Soil
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Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
7.
Leaf
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A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot, Leaves are collectively referred to as foliage, as in autumn foliage. Although leaves can be seen in different shapes, sizes and textures, typically a leaf is a thin, dorsiventrally flattened organ, borne above ground. Most leaves have distinctive upper surface and lower surface that differ in colour, hairiness, broad, flat leaves with complex venation are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In others, such as the clubmosses, with different evolutionary origins, some leaves, such as bulb scales are not above ground, and in many aquatic species the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls, furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from both in their structure and origin. Many structures of plants, such as the phyllids of mosses and liverworts and even of some foliose lichens. Leaves are the most important organs of most vascular plants and these are then further processed by chemical synthesis into more complex organic molecules such as cellulose, the basic structural material in plant cell walls. The plant must therefore bring these three together in the leaf for photosynthesis to take place. Once sugar has been synthesized, it needs to be transported to areas of growth such as the plant shoots and roots. Vascular plants transport sucrose in a tissue called the phloem. The phloem and xylem are parallel to each other but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much as the leaf as possible and they are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance plants adapted to windy conditions may have pendent leaves, such as in many willows, the flat, or laminar, shape also maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to photosynthesis the leaf is the site of transpiration and guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. For xerophytes the major constraint is not light flux or intensity, some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides
8.
Plant stem
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A stem is one of two main structural axes of a vascular plant, the other being the root. The stem is divided into nodes and internodes, The nodes hold one or more leaves. Adventitious roots may also be produced from the nodes, the internodes distance one node from another. The term shoots is often confused with stems, shoots generally refers to new plant growth including both stems and other structures like leaves or flowers. In most plants stems are located above the surface but some plants have underground stems. Stems have four main functions which are, Support for and the elevation of leaves, flowers, the stems keep the leaves in the light and provide a place for the plant to keep its flowers and fruits. Transport of fluids between the roots and the shoots in the xylem and phloem Storage of nutrients Production of new living tissue, the normal lifespan of plant cells is one to three years. Stems have cells called meristems that annually generate new living tissue, Stems are often specialized for storage, asexual reproduction, protection or photosynthesis, including the following, Acaulescent – used to describe stems in plants that appear to be stemless. Actually these stems are just extremely short, the leaves appearing to rise out of the ground. Arborescent – tree like with woody stems normally with a single trunk, branched – aerial stems are described as being branched or unbranched Bud – an embryonic shoot with immature stem tip. Bulb – a short underground stem with fleshy storage leaves attached, e. g. onion, daffodil. Bulbs often function in reproduction by splitting to form new bulbs or producing small new bulbs termed bulblets, bulbs are a combination of stem and leaves so may better be considered as leaves because the leaves make up the greater part. Caespitose – when stems grow in a mass or clump or in low growing mats. Cladode – a flattened stem that appears more-or-less leaf like and is specialized for photosynthesis, climbing – stems that cling or wrap around other plants or structures. Corm – a short enlarged underground, storage stem, e. g. taro, decumbent – stems that lie flat on the ground and turn upwards at the ends. Fruticose – stems that grow shrublike with woody like habit, herbaceous – non woody, they die at the end of the growing season. Pedicel – stems that serve as the stalk of a flower in an inflorescence or infrutescence. Peduncle – a stem that supports an inflorescence Prickle – a sharpened extension of the outer layers
9.
Root
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In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. Roots can also be aerial or aerating, that is growing up above the ground or especially above water, furthermore, a stem normally occurring below ground is not exceptional either. Therefore, the root is best defined as the non-leaf, non-nodes bearing parts of the plants body, however, important internal structural differences between stems and roots exist. The fossil record of roots – or rather, infilled voids where roots rotted after death – spans back to the late Silurian and their identification is difficult, because casts and molds of roots are so similar in appearance to animal burrows. They can be discriminated using a range of features, the first root that comes from a plant is called the radicle. In response to the concentration of nutrients, roots also synthesise cytokinin, Roots often function in storage of food and nutrients. The roots of most vascular plant species enter into symbiosis with fungi to form mycorrhizae. In its simplest form, the root architecture refers to the spatial configuration of a plant’s root system. This system can be complex and is dependent upon multiple factors such as the species of the plant itself, the composition of the soil. The configuration of root systems serves to support the plant, compete with other plants. Roots grow to specific conditions, which, if changed, can impede a plants growth. For example, a system that has developed in dry soil may not be as efficient in flooded soil, yet plants are able to adapt to other changes in the environment. Root architecture plays the important role of providing a supply of nutrients and water as well as anchorage. The main terms used to classify the architecture of a system are, Branch magnitude. Root angle, the angle of a lateral root’s base around the parent root’s circumference, the angle of a lateral root from its parent root. Link radius, the diameter of a root, all components of the root architecture are regulated through a complex interaction between genetic responses and responses due to environmental stimuli. These developmental stimuli are categorised as intrinsic, the genetic and nutritional influences, or extrinsic, the main hormones and respective pathways responsible for root architecture development include, Auxin – Auxin promotes root initiation, root emergence and primary root elongation. Cytokinins – Cytokinins regulate root apical meristem size and promote lateral root elongation, gibberellins – Together with ethylene they promote crown primordia growth and elongation
10.
Storage organ
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A storage organ is a part of a plant specifically modified for storage of energy or water. Storage organs often grow underground, where they are protected from attack by herbivores. Plants that have a storage organ are called geophytes in the Raunkiær plant life-form classification system. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions, storage organs may act as perennating organs. These are used by plants to survive adverse periods in the plants life-cycle, during these periods, parts of the plant die and then when conditions become favourable again, re-growth occurs from buds in the perennating organs. For example geophytes growing in woodland under deciduous trees die back to storage organs during summer when tree leaf cover restricts light. However, perennating organs need not be storage organs, equally, storage organs need not be perennating organs. Many succulents have leaves adapted for storage, which they retain in adverse conditions. g. Intermediates and combinations of the above are found, making classification difficult. As an example of an intermediate, the tuber of Cyclamen arises from the stem of the seedling, which forms the junction of the roots and stem of the mature plant. In some species come from the bottom of the tuber, suggesting that it is a stem tuber, in others roots come largely from the top of the tuber. As an example of a combination, juno irises have both bulbs and storage roots, underground storage organs used for food may be generically called root vegetables, although this phrase should not be taken to imply that the class only includes true roots. Succulents are plants which are adapted to periods of drought by their ability to store moisture in specialized storage organs. Leaf succulents store water in their leaves, which are thickened, fleshy. They may also contain mucilagenous compounds, some leaf succulents have leaves which are distributed along the stem in a similar fashion to non-succulent species, their stems may also be succulent. In others, the leaves are more compact, forming a rosette, pebble-plants or living stones have reduced their leaves to just two, forming a fleshy body, only the top of which may be visible above ground. Stem succulents are generally either leafless or have leaves which can be shed in the event of drought. Photosynthesis is then taken over by the stems, as with leaf succulents, stems may be covered with a waxy coating or fine hairs to reduce evaporation
11.
Horticulture
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Horticulture is the branch of agriculture that deals with the art, science, technology, and business of growing plants. It includes the cultivation of plants, fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and non-food crops such as grass and ornamental trees. It also includes plant conservation, landscape restoration, landscape and garden design, construction, and maintenance, inside agriculture, horticulture contrasts with extensive field farming as well as animal husbandry. Horticulturists apply their knowledge, skills, and technologies used to grow intensively produced plants for food and non-food uses. Their work involves plant propagation and cultivation with the aim of improving plant growth, yields, quality, nutritional value, and resistance to insects, diseases and they work as gardeners, growers, therapists, designers, and technical advisors in the food and non-food sectors of horticulture. Horticulture even refers to the growing of plants in a field or garden, hortus is cognate with the native English word yard and also the borrowed word garden. Turf management includes all aspects of the production and maintenance of grass for sports. Floriculture includes the production and marketing of floral crops, landscape horticulture includes the production, marketing and maintenance of landscape plants. Olericulture includes the production and marketing of vegetables, pomology includes the production and marketing of pome fruits. Viticulture includes the production and marketing of grapes, oenology includes all aspects of wine and winemaking. Postharvest physiology involves maintaining the quality of and preventing the spoilage of plants, Horticulture has a very long history. The practice of horticulture can be retraced for many thousands of years, the cultivation of taro and yam in Papua New Guinea dates back to at least 6950–6440 cal BP. In the Pre-Columbian Amazon Rainforest, natives are believed to have used biochar to enhance productivity by smoldering plant waste. European settlers called it Terra Preta de Indio, in forest areas such horticulture is often carried out in swiddens. A characteristic of horticultural communities is that trees are often to be found planted around communities or specially retained from the natural ecosystem. Horticulture primarily differs from agriculture in two ways, first, it generally encompasses a smaller scale of cultivation, using small plots of mixed crops rather than large fields of single crops. Secondly, horticultural cultivations generally include a variety of crops. Agricultural cultivations however as a focus on one primary crop
12.
Ornamental plant
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Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as houseplants, for cut flowers and specimen display. The cultivation of these, called floriculture, forms a branch of horticulture. Commonly, ornamental plants are grown for the display of aesthetic features including, leaves, scent, overall foliage texture, fruit, stem and bark, and aesthetic form. In some cases, unusual features may be considered to be of interest, such as the prominent thorns of Rosa sericea, in all cases, their purpose is for the enjoyment of gardeners, visitors, and the public institutions. Similarly certain trees may be called ornamental trees and this term is used when they are used as part of a garden, park, or landscape setting, for instance for their flowers, their texture, form, size and shape, and other aesthetic characteristics. In some countries trees in utilitarian landscape use such as screening, for plants to be considered to be ornamental, they may require specific work and activity by a gardener. Ornamental plants and trees are distinguished from utilitarian and crop plants, such as used for agriculture and vegetable crops. This does not preclude any type of plant being grown both for ornamental qualities in the garden, and for utilitarian purposes in other settings. Thus lavender is typically grown as a plant in gardens. The term ornamental plant is used here in the sense that it is generally used in the horticultural trades. The term largely corresponds to garden plant, though the latter is less precise. Ornamental plants are plants which are grown for display purposes, rather than functional ones, Ornamental plants are the keystone of ornamental gardening, and they come in a range of shapes, sizes and colors suitable to a broad array of climates, landscapes, and gardening needs. Some ornamental plants are grown for showy foliage and their foliage may be deciduous, turning bright orange, red, and yellow before dropping off in the fall, or evergreen, in which case it stays green year-round. Other ornamental plants are cultivated for their blooms, flowering ornamentals are a key aspect of many gardens, with many flower gardeners preferring to plant a variety of flowers so that the garden is continuously in flower through the spring and summer. Media related to Ornamental plants at Wikimedia Commons
13.
Aizoaceae
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Aizoaceae or Ficoidaceae is a family of dicotyledonous flowering plants containing 135 genera and about 1900 species. They are commonly known as stone plants, carpet weeds or vygies, species that resemble stones or pebbles are sometimes called mesembs. Several species are known as ice plants because of the glistening globular bladder cells covering their stems, fruit, the family is widely recognised by taxonomists, although once it went by the botanical name Ficoideae, now disallowed. The APG II system of 2003 also recognises the family, the APG II system also classes the former families Mesembryanthemaceae Fenzl, Sesuviaceae Horan. and Tetragoniaceae Link under the family Aizoaceae. Most species in this family are endemic to arid or semiarid parts of southern Africa, but a few are from Australia, most of these species are succulents and belong to the subfamilies Mesembryanthemoideae and Ruschioideae and are loosely termed mesems or mesembs. Most fig-marigolds are herbaceous, rarely somewhat woody, with stems growing erect or prostrate. Leaves are simple, opposite or alternate, and more or less succulent with entire margins, Flowers are perfect in most species, actinomorphic, and appear singularly or in few-flowered cymes developing from the leaf axils. Sepals are typically five and more or less connate below, however, some species have numerous linear petals derived from staminodes. The fruit is a capsule one to numerous seeds per cell. A few species have been introduced and become invasive. They are called ice plant because they have bladder-like hairs on the surface that reflect and refract light in a manner to make it appear that they sparkle like ice crystals. Several Aizoaceae are edible, including, Carpobrotus edulis and Mesembryanthemum crystallinum have edible leaves, a species known as New Zealand spinach is grown as a garden plant in somewhat dry climates and used as an alternative to spinach in upscale salads. Carpobrotus edulis was introduced to California to stabilize soil along railroad tracks, ice plant thrives in southern California. People surround their property with it believing it will act as a firewall to protect against wildfires, ice plant contains so much water, it does not burn if carefully maintained. Aizoanthemum Dinter ex Friedrich Aizoon L. Galenia L. Gunniopsis Pax Plinthus Fenzl Tetragonia L. Cypselea Turpin Sesuvium L. Trianthema L. Tribulocarpus S. Moore Zaleya Burm. f, corbichonia Gisekia Herreanthus Limeum Ophthalmophyllum Saphesia Bittrich V. H. E. K. Hartmann. Cornelia Klak, Angeline Khunou, Gail Reeves, Terry Hedderson, a phylogenetic hypothesis for the Aizoaceae based on four plastid DNA regions. Aizoaceae in L. Watson and M. J. Dallwitz, the families of flowering plants NCBI Taxonomy Browser P. Chesselet. Interactive Mesembs2 Plants of southern Africa, SANBI Aizoaceae of South Africa Family Aizoaceae Flowers in Israel
14.
Crassulaceae
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The Crassulaceae, also known as the stonecrop family or the orpine family, are a family of dicotyledons with succulent leaves. They are generally herbaceous but there are some subshrubs, and relatively few treelike or aquatic plants and they are found worldwide, but mostly occur in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce. The family includes approximately 1400 species and 34 or 35 genera, although the number of genera is disputed and depends strongly on the circumscription of Sedum. Familiar species include the plant or friendship tree, Crassula ovata. Crassulaceae is a group within the core eudicots as a primitive member of the Rosidae. Some older classifications included Crassulaceae in Rosales, but newer schemes treat them in the order Saxifragales, classification within the family is difficult because many of the species hybridize readily, both in the wild and in cultivation. Six subfamilies of Crassulaceae were described by Berger in 1930, Crassuloideae, Kalanchiodeae, Cotyledonoideae, Sempervivoideae, Sedoideae, though various revisions since have proposed four, three, and two subfamilies, many botanists still use Bergers classification, although some of the subfamilies are polyphyletic. Molecular phylogenetics has shown that morphological characters and chromosome numbers are so labile in the family that they cannot be used reliably to infer evolution, crassulacean acid metabolism is named after the family, because the pathway was first discovered in crassulacean plants. It is one of the few families that still has CAM as an active, photosynthetic pathway, Crassulaceae evolved approximately 100–60 million years ago in Eastern Africa or in the Mediterranean region, though Africa is more widely recognized as the place of origin. Other sources suggest that Crassulaceae evolved approximately 70 million years ago together with families Penthoraceae and Haloragaceae, the taxon is considered to have a gradual evolution, whereas there is a basal split between Crassuloideae and the rest of the family. The Crassuloideae lineage migrated into Southern Africa and other genera within Sedoideae migrated to Europe, Asia, Northern, illustrated Handbook of Succulent Plants, Crassulaceae ISBN 3-540-41965-9 Data related to Crassulaceae at Wikispecies Crassulaceae page Crassulaceae in Topwalks
15.
Aloe polyphylla
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Aloe polyphylla is a species in the genus Aloe that is endemic to the Kingdom of Lesotho in the Drakensberg mountains. It is well known for its symmetrical, five-pointed spiral growth habit. Aloe polyphylla is commonly known as the spiral aloe in English, kroonaalwyn in Afrikaans, the species epithet polyphylla means many-leaved in Greek. Taxonomically, it part of the Rhodacanthae series of very closely related Aloe species, together with Aloe glauca, Aloe lineata. Aloe polyphylla is a stemless aloe and grows its leaves in a distinctive spiral shape which may be clockwise or anti-clockwise. The plants do not seem to sucker or produce offshoots, but from the germination of their seeds they can form small, the fat, wide, serrated, gray-green leaves have sharp, dark leaf-tips and grow in the five spiral rows. This aloe flowers at the beginning of summer, producing flowers that range in colour from red to pink and occasionally yellow, at the head of robust. The spiral aloe grows in high, mountainous, grassy slopes at altitudes between 2,000 and 2,599 m, and sometimes higher on east-facing slopes, here it clings to rocky crevices and well-drained scree slopes. The climate is cool in the summer and in the winter the aloes are often covered in deep snow, the region also has a very high rainfall and this moisture is augmented by the clouds which engulf the Lesotho mountain peaks. The species is sought after as an ornamental but is difficult to cultivate. In South Africa, buying or collecting the plant is a criminal offence, care and cultivation, ecological status, etc
16.
Xerophyte
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A xerophyte is a species of plant that has adapted to survive in an environment with little liquid water, such as a desert or an ice- or snow-covered region in the Alps or the Arctic. The morphology and physiology of xerophytes are variously adapted to conserve water, other species may be adapted to survive long periods of desiccation of their tissues, during which their metabolic activity may effectively shut down. Plants with such morphological and physiological adaptations are xeromorphic, Plants absorb water from the soil, which then evaporates from their outer surfaces, this process is known as transpiration. In dry environments, a plant would evaporate water faster than the rate at which water was replaced in the soil. To reduce this effect, xerophytic plants exhibit a variety of specialized adaptations to survive in such conditions, cacti and other succulents are commonly found in deserts, where there is little rainfall. Likewise, chaparral plants are adapted to Mediterranean climates, which have wet winters, Plants that live under arctic conditions also have a need for xerophytic adaptations, since water is unavailable for uptake when the ground is frozen. Succulent plants store water in their stems or leaves and they include the Cactaceae family, which has round stems and can store a lot of water. The leaves are vestigial, as in the case of cacti, wherein the leaves are reduced to spines. Xerophytes are commonly found in environments, where plants such as pineapples. Water is stored in the bulbs of plants, at or below ground level. They may be dormant during drought conditions and are, therefore, if the water potential inside a leaf is higher than outside, the water vapour will diffuse out of the leaf down this gradient. This loss of water vapour from the leaves is called transpiration, transpiration is natural and inevitable for plants, and much water is lost through this process. However, it is vital that plants living in dry conditions are adapted so as to reduce water loss and decrease the size of the open stomata. It is important for a plant living in conditions to conserve water because, without enough water. If the plant loses too much water, it will pass its permanent wilting point and it is important to note, that whilst it is vital to keep stomata closed, they have to be opened for gaseous exchange in photosynthesis. Xerophytic plants may have similar shapes, forms, and structures and look similar, even if the plants are not very closely related. For example, some species of cacti, which evolved only in the Americas, may similar to Euphorbias. An unrelated species of caudiciforms, plants with swollen bases that are used to store water, xerophytic plants can have less overall surface area than other plants, so reducing the area that is exposed to the air and reducing water loss by evaporation
17.
Crassula helmsii
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Crassula helmsii, known as swamp stonecrop or New Zealand pigmyweed, is an aquatic or semiterrestrial species of succulent plant in the family Crassulaceae. Originally found in Australia and New Zealand, it has introduced around the world. In the United Kingdom, this plant is one of five introduced aquatic plants which were banned from sale from April 2014 and this is the first ban of its kind in the country. The shoots are rather stiff, carrying narrow parallel-sided leaves in opposite pairs, small white flowers with four petals are produced in summer on long stalks arising from the upper leaf axils. The flowers are always above water, the plant grows on the muddy margins of ponds where it forms carpets with 100% cover, or semi-submerged in deeper water, or totally submerged with elongated stems. It does not die back in winter, C. helmsii is able to grow fully submerged in a cool water aquarium or as a submersed or marginal plant in a pond. Once established it can grow vigorously and may need to be trimmed back, schedule 9 of the UK Wildlife and Countryside Act 1981 lists this plant as one that cannot be caused to grow in the wild. BioImages Status in N. Ireland includes an introduction on UK information Flora of N. Ireland - illustrated Close up of flower Ecological information
18.
Bromeliaceae
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They are among the basal families within the Poales and are unique because they are the only family within the order that has septal nectaries and inferior ovaries. These inferior ovaries characterize the Bromelioideae, a subfamily of the Bromeliaceae, the family includes both epiphytes, such as Spanish moss, and terrestrial species, such as the pineapple. Many bromeliads are able to water in a structure formed by their tightly-overlapping leaf bases. The largest bromeliad is Puya raimondii, which reaches 3–4 m tall in vegetative growth with a flower spike 9–10 m tall, Bromeliads are plants that are adapted to various climates. Foliage takes different shapes, from needle-thin to broad and flat, symmetrical to irregular, the foliage, which usually grows in a rosette, is widely patterned and colored. Leaf colors range from maroon, through shades of green, to gold, varieties may have leaves with red, yellow, white and cream variations. Others may be spotted with purple, red, or cream, while others have different colors on the tops, the inflorescences produced by bromeliads are also regarded as considerably more diverse than any other plant family. Some flower spikes may reach 10 meters tall, while others only measure 2–3 mm across, upright stalks may be branched or simple with spikes retaining their color from two weeks up to 12 months, depending on species. In some species, the flower remains unseen, growing deep in the base of the plants, root systems vary according to plant type. Terrestrial bromeliad species have complex systems that gather water and nutrients, while epiphytic bromeliads only grow hard, wiry roots to attach themselves to trees. Some bromeliads are faintly scented, while others are heavily perfumed, blooms from the species Tillandsia cyanea have a fragrance resembling that of clove spice. One study found 175,000 bromeliads per hectare in one forest, a wide variety of organisms takes advantage of the pools of water trapped by bromeliads. A study of 209 plants from the Ecuadorian lowlands identified 11,219 animals, representing more than 300 distinct species, examples include some species of ostracods, small salamanders about 2.5 cm in length, and tree frogs. Some bromeliads even form homes for other species of bromeliads, plants in the Bromeliaceae are widely represented in their natural climates across the Americas. One species can be found in Africa and they can be found at altitudes from sea level to 4200 meters, from rainforests to deserts. 1814 species are epiphytes, some are lithophytes, and some are terrestrial, Bromeliads often serve as phytotelmata, accumulating water between their leaves. The aquatic habitat created as a result is host to an array of invertebrates. These bromeliad invertebrates benefit their hosts by increasing nitrogen uptake into the plant, Bromeliads are among the more recent plant groups to have emerged
19.
Crassulacean acid metabolism
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Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, the pre-collected CO2 is concentrated around the enzyme RuBisCO, increasing photosynthetic efficiency. This metabolism was first studied in plants of the Crassulaceae family, the first time it was studied, Crassula was used as a model organism. The term CAM may have coined by Ranson and Thomas in 1940. It was observed by the botanists Ranson and Thomas, in the Crassulaceae family of succulents and its name refers to acid metabolism in Crassulaceae, not the metabolism of crassulacean acid. CAM is an adaptation for increased efficiency in the use of water, during the night, a plant employing CAM has its stomata open, allowing CO2 to enter and be fixed as organic acids that are stored in vacuoles. During the day the stomata are closed, and the carbon is released to the Calvin cycle so that photosynthesis may take place, the carbon dioxide is fixed in the cytoplasm of mesophyll cells by a PEP reaction similar to that of C4 pathway. But, unlike the C4 mechanism, the organic acids are stored in vacuoles for later use. The latter cannot operate during the night because the reactions that provide it with ATP. The most important benefit of CAM to the plant is the ability to leave most leaf stomata closed during the day, plants employing CAM are most common in arid environments, where water comes at a premium. Plants using only C3 carbon fixation, for example, lose 97% of the water they uptake through the roots to transpiration - a high cost avoided by plants able to employ CAM. The C4 pathway bears resemblance to CAM, both act to concentrate CO2 around RuBisCO, thereby increasing its efficiency, CAM concentrates it temporally, providing CO2 during the day, and not at night, when respiration is the dominant reaction. C4 plants, in contrast, concentrate CO2 spatially, with a RuBisCO reaction centre in a bundle sheath cell being inundated with CO2, at low temperatures, plants using CAM open their stomata, CO2 molecules diffuse into the spongy mesophylls intracellular spaces and then into the cytoplasm. Here, they can meet phosphoenolpyruvate, which is a phosphorylated triose, during this time, the plants are synthesizing a protein called PEP carboxylase kinase, whose expression can be inhibited by high temperatures and the presence of malate. PEP-C kinase phosphorylates its target enzyme PEP carboxylase, phosphorylation dramatically enhances the enzymes capability to catalyze the formation of oxalacetate, which can be subsequently transformed into malate by NAD+ malate dehydrogenase. Malate is then transported via malate shuttles into the vacuole, where it is converted into the storage form malic acid, in contrast to PEP-C kinase, PEP-C is synthesized all the time but almost inhibited at daylight either by dephosphorylation via PEP-C phosphatase or directly by binding malate. The latter is not possible at low temperatures, since malate is efficiently transported into the vacuole, in daylight, plants using CAM close their guard cells and discharge malate that is subsequently transported into chloroplasts. There, depending on plant species, it is cleaved into pyruvate, CO2 is then introduced into the Calvin cycle, a coupled and self-recovering enzyme system, which is used to build branched carbohydrates
20.
Stoma
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In botany, a stoma, also called a stomate, is a pore, found in the epidermis of leaves, stems, and other organs, that is used to control gas exchange. The pore is bordered by a pair of specialized cells known as guard cells that are responsible for regulating the size of the stomatal opening. The term is used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself. Air enters the plant through these openings by gaseous diffusion, and contains carbon dioxide and oxygen, oxygen produced as a by-product of photosynthesis diffuses out to the atmosphere through these same openings. Also, water vapor is released into the atmosphere through these pores in a process called transpiration, stomata are present in the sporophyte generation of all land plant groups except liverworts. Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis, monocotyledons, on the other hand, usually have the same number of stomata on the two epidermes. In plants with floating leaves, stomata may be only on the upper epidermis. Most tree species have leaves only on the lower surface, size varies across species, with end-to-end lengths ranging from 10 to 80 µm and width ranging from a few to 50 µm. Carbon dioxide, a key reactant in photosynthesis, is present in the atmosphere at a concentration of about 400 ppm, most plants require the stomata to be open during daytime. The air spaces in the leaf are saturated with water vapour, which exits the leaf through the stomata, therefore, plants cannot gain carbon dioxide without simultaneously losing water vapour. Ordinarily, carbon dioxide is fixed to ribulose-1, 5-bisphosphate by the enzyme RuBisCO in mesophyll cells exposed directly to the air spaces inside the leaf. For both of these reasons, RuBisCo needs high carbon dioxide concentrations, which means wide stomatal apertures and, as a consequence, narrower stomatal apertures can be used in conjunction with an intermediary molecule with a high carbon dioxide affinity, PEPcase. Retrieving the products of carbon fixation from PEPCase is in an energy-intensive process, a group of mostly desert plants called CAM plants open their stomata at night, use PEPcarboxylase to fix carbon dioxide and store the products in large vacuoles. The following day, they close their stomata and release the carbon dioxide fixed the previous night into the presence of RuBisCO and this saturates RuBisCO with carbon dioxide, allowing minimal photorespiration. This approach, however, is limited by the capacity to store fixed carbon in the vacuoles. It is not entirely certain how these responses work, however, the basic mechanism involves regulation of osmotic pressure. When conditions are conducive to stomatal opening, a proton pump drives protons from the guard cells and this means that the cells electrical potential becomes increasingly negative. The negative potential opens potassium voltage-gated channels and so an uptake of ions occurs
21.
Photosynthesis
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Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms activities. In most cases, oxygen is released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, such organisms are called photoautotrophs, in plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, in the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate. Using the ATP and NADPH produced by the light-dependent reactions, the compounds are then reduced and removed to form further carbohydrates. Cyanobacteria appeared later, the oxygen they produced contributed directly to the oxygenation of the Earth. Today, the rate of energy capture by photosynthesis globally is approximately 130 terawatts. Photosynthetic organisms also convert around 100–115 thousand million tonnes of carbon into biomass per year. Photosynthetic organisms are photoautotrophs, which means that they are able to synthesize food directly from carbon dioxide, however, not all organisms that use light as a source of energy carry out photosynthesis, photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants, algae, and cyanobacteria, photosynthesis releases oxygen and this is called oxygenic photosynthesis and is by far the most common type of photosynthesis used by living organisms. Although there are differences between oxygenic photosynthesis in plants, algae, and cyanobacteria, the overall process is quite similar in these organisms. There are also varieties of anoxygenic photosynthesis, used mostly by certain types of bacteria. Carbon dioxide is converted into sugars in a process called carbon fixation, photosynthesis provides the energy in the form of free electrons that are used to split carbon from carbon dioxide that is then used to fix that carbon once again as carbohydrate. Carbon fixation is a redox reaction, so photosynthesis supplies the energy that drives both process. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the energy-storage molecules ATP, during the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide. Most organisms that utilize oxygenic photosynthesis use visible light for the light-dependent reactions, some organisms employ even more radical variants of photosynthesis. Some archea use a method that employs a pigment similar to those used for vision in animals. The bacteriorhodopsin changes its configuration in response to sunlight, acting as a proton pump and this produces a proton gradient more directly, which is then converted to chemical energy
22.
Dew
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Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening due to condensation. As the exposed surface cools by radiating its heat, atmospheric moisture condenses at a greater than that at which it can evaporate. When temperatures are low enough, dew takes the form of ice, Dew should not be confused with guttation, which is the process by which plants release excess water from the tips of their leaves. Water vapor will condense into droplets depending on the temperature, the temperature at which droplets form is called the dew point. When surface temperature drops, eventually reaching the dew point, atmospheric water vapor condenses to form small droplets on the surface and this process distinguishes dew from those hydrometeors, which form directly in air that has cooled to its dew point, such as fog or clouds. The thermodynamic principles of formation, however, are the same, Dew is usually formed at night. Adequate cooling of the surface typically takes place when it more energy by infrared radiation than it receives as solar radiation from the sun. Poor thermal conductivity restricts the replacement of such losses from deeper ground layers, preferred objects of dew formation are thus poor conducting or well isolated from the ground, and non-metallic, while shiny metal coated surfaces are poor infrared radiators. Preferred weather conditions include the absence of clouds and little water vapor in the atmosphere to minimize greenhouse effects. Typical dew nights are considered calm, because the wind transports warmer air from higher levels to the cold surface. However, if the atmosphere is the source of moisture. The highest optimum wind speeds could be found on arid islands, if the wet soil beneath is the major source of vapor, however, wind always seems adverse. The processes of dew formation do not restrict its occurrence to the night and they are also working when eyeglasses get steamy in a warm, wet room or in industrial processes. However, the term condensation is preferred in these cases, a classical device for dew measurement is the drosometer. A small, artificial condenser surface is suspended from an arm attached to a pointer or a pen that records the changes of the condenser on a drum. Besides being very sensitive, however, this, like all artificial surface devices. The actual amount of dew in a place is strongly dependent on surface properties. Further methods include estimation by means of comparing the droplets to standardized photographs, some of these methods include guttation, while others only measure dewfall and/or distillation
23.
Plant cuticle
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A plant cuticle is a protecting film covering the epidermis of leaves, young shoots and other aerial plant organs without periderm. It consists of lipid and hydrocarbon polymers impregnated with wax, and is synthesized exclusively by the epidermal cells, the plant cuticle is a layer of lipid polymer impregnated with waxes that is present on the outer surfaces of the primary organs of all vascular land plants. The cuticle is composed of an insoluble cuticular membrane impregnated by, cutin, a polyester polymer composed of inter-esterified omega hydroxy acids which are cross-linked by ester and epoxide bonds, is the best-known structural component of the cuticular membrane. The cuticle can also contain a non-saponifiable hydrocarbon polymer known as Cutan, aerial organs of many plants, such as the leaves of the sacred lotus have ultra-hydrophobic and self-cleaning properties that have been described by Barthlott and Neinhuis. The lotus effect has applications in biomimetic technical materials, dehydration protection provided by a maternal cuticle improves offspring fitness in the moss Funaria hygrometrica. and in the sporophytes of all vascular plants. The waxy sheet of cuticle also functions in defense, forming a barrier that resists penetration by virus particles, bacterial cells
24.
Mucilage
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Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. It is a glycoprotein and an exopolysaccharide. Mucilage in plants plays a role in the storage of water and food, seed germination, cacti and flax seeds especially are rich sources of mucilage. Exopolysaccharides are the most stabilising factor for microaggregates and are distributed in soils. Therefore, exopolysaccharide-producing soil algae play a role in the ecology of the worlds soils. The substance covers the outside of, for example, unicellular or filamentous green algae, amongst the green algae especially, the group Volvocales are known to produce exopolysaccharides at a certain point in their life cycle. It occurs in almost all plants, but usually in small amounts and it is frequently associated with substances like tannins and alkaloids. Mucilage has a purpose in some carnivorous plants. The plant genera Drosera, Pinguicula, and others have leaves studded with mucilage-secreting glands and it is used in medicine as it relieves irritation of mucous membranes by forming a protective film. Traditionally, marshmallows were made from the extract of the root of the marshmallow plant as a cough medicine. The inner bark of the elm, a North American tree species, has long been used as a demulcent and is still produced commercially for that purpose. Mucilage mixed with water has been used as a glue, especially for bonding paper items such as labels, postage stamps, and envelope flaps. Differing types and varying strengths of mucilage can also be used for other applications, including gluing labels to metal cans, wood to china. During the fermentation of nattō soybeans, extracellular enzymes produced by the bacterium Bacillus natto react with sugars to produce mucilage. The amount and viscosity of the mucilage are important nattō characteristics, contributing to nattōs unique taste, the mucilage of two kinds of insectivorous plants, sundew and butterwort, is used for the traditional production of a variant of the yoghurt-like Swedish dairy product called filmjölk
25.
Steppe
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In South Africa they are referred to as Veld. The prairie is an example of a steppe, though it is not usually called such and it may be semi-desert, or covered with grass or shrubs or both, depending on the season and latitude. The term is used to denote the climate encountered in regions too dry to support a forest. The soil is typically of chernozem type, steppes are usually characterized by a semi-arid and continental climate. Extremes can be recorded in the summer of up to 45 °C and in winter, besides this huge difference between summer and winter, the differences between day and night are also very great. In the highlands of Mongolia,30 °C can be reached during the day with sub-zero °C readings at night, the mid-latitude steppes can be summarized by hot summers and cold winters, averaging 250–510 mm of precipitation per year. Precipitation level alone is not what defines a steppe climate, potential evapotranspiration must also be taken into account, the Eurasian Grass-Steppe of the temperate grasslands, savannas, and shrublands had a role in the spread of the horse, the wheel, and the Indo-European languages. The Indo-European expansion and diverse invasions of horse archer civilizations of the steppe eventually led to, the Pannonian Plain is another steppe region in eastern Europe, primarily Hungary. Another large steppe area is located in the central United States, western Canada, the shortgrass prairie steppe is the westernmost part of the Great Plains region. The Channeled Scablands in Southern British Columbia and Washington State is an example of a region in North America outside of the Great Plains. In South America, cold steppe can be found in Patagonia, relatively small steppe areas can be found in the interior of the South Island of New Zealand. In Asia, a subtropical steppe can be found in semi-arid lands that fringe the Thar Desert of the Indian subcontinent, in Australia, subtropical steppe can be found in a belt surrounding the most severe deserts of the continent and around the Musgrave Ranges. Ecology and Conservation of Steppe-land Birds by Manuel B. Morales, Santi Mañosa, Jordi Camprodón, international Symposium on Ecology and Conservation of steppe-land birds
26.
Semi-arid climate
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A semi-arid climate or steppe climate is the climate of a region that receives precipitation below potential evapotranspiration, but not extremely. There are different kinds of climates, depending on such variables as temperature. Semi-arid climates tend to short or scrubby vegetation, with semi-arid areas usually dominated by either grasses or shrubs. To determine if a location has a climate, the precipitation threshold must first be determined. If the areas precipitation is less than the threshold but more than half the threshold. Hot semi-arid climates tend to be located in the tropics and subtropics and these climates tend to have hot, sometimes extremely hot, summers and warm to cool winters, with some to minimal precipitation. Hot semi-arid climates are most commonly found around the fringes of subtropical deserts, hot semi-arid climates are most commonly found in Africa, Australia and South Asia. In Australia, a portion of the Outback surrounding the central desert regions lies within the hot semi-arid climate regime. Hot semi-arid climates can also be found in North America, primarily in Mexico, areas of Texas near Mexico, cold semi-arid climates tend to be located in temperate zones or elevated portions in subtropical zones. They are typically found in continental interiors some distance from bodies of water. Cold semi-arid climates usually feature warm and dry summers, though their summers are not quite as hot as those of hot semi-arid climates. Unlike hot semi-arid climates, areas with cold semi-arid climates tend to have cold winters and these areas usually see some snowfall during the winter, though snowfall is much lower than at locations at similar latitudes with more humid climates. These large diurnal temperature variations are seen in hot semi-arid climates. Cold semi-arid climates are most commonly found in Asia and North America, however, they can also be found in Northern Africa, South Africa, Europe, sections of South America and sections of interior southern Australia and New Zealand. As a result of this, some areas can have climates that are classified as hot or cold depending on the isotherm used. One such location is San Diego, California, which has cool summers for the due to prevailing winds off the ocean. Arid Forest Research Institute Continental climate Dust Bowl Goyders Line Pallisers Triangle Köppen climate classification Wave height Ustic
27.
Desert
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A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation, about one third of the land surface of the world is arid or semi-arid. This includes much of the regions where little precipitation occurs. Deserts can be classified by the amount of precipitation falls, by the temperature that prevails. Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces, although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter and the resulting fragments and this picks up particles of sand and dust and wafts them aloft in sand or dust storms. Wind-blown sand grains striking any solid object in their path can abrade the surface, rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes, other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones. These areas are known as desert pavements and little further erosion takes place, other desert features include rock outcrops, exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate, there may be underground sources of water in the form of springs and seepages from aquifers. Where these are found, oases can occur, plants and animals living in the desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles, some annual plants germinate, bloom and die in the course of a few weeks after rainfall while other long-lived plants survive for years and have deep root systems able to tap underground moisture. Animals need to cool and find enough food and water to survive. Many are nocturnal and stay in the shade or underground during the heat of the day and they tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine. Some animals remain in a state of dormancy for long periods and they then reproduce rapidly while conditions are favorable before returning to dormancy. People have struggled to live in deserts and the surrounding lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, the cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Many trade routes have been forged across deserts, especially across the Sahara Desert, large numbers of slaves were also taken northwards across the Sahara
28.
Precipitation
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In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel, Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and precipitates. Thus, fog and mist are not precipitation but suspensions, because the vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated, Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers, moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain. This process is active when freezing rain is occurring. A stationary front is often present near the area of freezing rain, provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. Eventually, the droplets will grow large enough to form raindrops. Lake-effect snowfall can be locally heavy, thundersnow is possible within a cyclones comma head and within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation, on the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. The movement of the trough, or intertropical convergence zone. Precipitation is a component of the water cycle, and is responsible for depositing the fresh water on the planet. Approximately 505,000 cubic kilometres of water falls as precipitation each year,398,000 cubic kilometres of it over the oceans and 107,000 cubic kilometres over land. Given the Earths surface area, that means the globally averaged annual precipitation is 990 millimetres, Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Precipitation may occur on celestial bodies, e. g. when it gets cold, Mars has precipitation which most likely takes the form of frost. Precipitation is a component of the water cycle, and is responsible for depositing most of the fresh water on the planet. Approximately 505,000 km3 of water falls as precipitation each year,398,000 km3 of it over the oceans, given the Earths surface area, that means the globally averaged annual precipitation is 990 millimetres. Mechanisms of producing precipitation include convective, stratiform, and orographic rainfall, Precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with the surface, or ice
29.
Epiphyte
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An epiphyte is a plant that grows harmlessly upon another plant and derives its moisture and nutrients from the air, rain, and sometimes from debris accumulating around it. Epiphytes differ from parasites in that epiphytes grow on plants for physical support. An epiphytic organism that is not a plant is called an epibiont, epiphytes are usually found in the temperate zone or in the tropics. Epiphyte species make good houseplants due to their water and soil requirements. Epiphytes provide a rich and diverse habitat for other organisms including animals, fungi, bacteria, epiphyte is one of the subdivisions of the Raunkiær system. The term epiphytic derives from the Greek epi- and phyton, epiphytic plants are sometimes called air plants because they do not root in soil. However, there are aquatic species of algae, including seaweeds. The best-known epiphytic plants include mosses, orchids, and bromeliads such as Spanish moss, 89% of epiphyte species are flowering plants. The second largest group are the ferns, with about 2800 species. In fact, about one third of all ferns are epiphytes, the third largest group is clubmosses, with 190 species, followed by a handful of species in each of the spikemosses, other ferns, Gnetales, and cycads. Epiphytic organisms usually derive only physical support and not nutrition from their host, parasitic and semiparasitic plants growing on other plants are not true epiphytes, but are still epiphytic in habit. Some epiphytic plants are trees that begin their lives high in the forest canopy. Over decades they send roots down the trunk of a host tree eventually overpowering and replacing it, the strangler fig and the northern rātā of New Zealand are examples of this. Epiphytes that end up as free standing trees are also called hemiepiphytes, epiphytic plants use photosynthesis for energy and obtain moisture from the air or from dampness on the surface of their hosts. Roots may develop primarily for attachment, and specialized structures may be used to collect or hold moisture, the first important monograph on epiphytic plant ecology was written by A. F. W. Assemblages of large epiphytes occur most abundantly in moist tropical forests, in Europe there are no dedicated epiphytic plants using roots, but rich assemblages of mosses and lichens grow on trees in damp areas, and the common polypody fern grows epiphytically along branches. Rarely, grass, small bushes or small trees may grow in suspended soils up trees, epiphytic plants attached to their hosts high in the canopy have an advantage over herbs restricted to the ground where there is less light and herbivores may be more active. Epiphytic plants are important to certain animals that may live in their water reservoirs, such as some types of frogs
30.
Tillandsia
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Airplant is a common name for plants in this genus. Most Tillandsia species are epiphytes – i. e. they normally grow without soil while attached to other plants, some are aerophytes or air plants, which have no roots and grow on shifting desert soil. Generally, the thinner-leafed varieties grow in areas and the thick-leafed varieties in areas more subject to drought. Most species absorb moisture and nutrients through the leaves from rain, dew, dust, decaying leaves and insect matter, Tillandsias are epiphytes and need no soil because water and nutrients are absorbed through the leaves. The roots are used as anchors. Propagation is by seeds or by offsets called pups, a single plant could yield up to a dozen pups. Offsets can be separated when about 2/3 the size of their mother to encourage a new colony, although not normally cultivated for their flowers, some Tillandsia will bloom on a regular basis. However, while some may exhibit a spectacular inflorescence, most flowers are generally small, the flowers of some species may change color through the blooming cycle. Some species or varieties produce fragrant flowers, in addition, it is quite common for some species to take on a different leaf color, called blushing, when about to flower. This is an indication that the plant is monocarpic but offsets around the plant will continue to thrive. Blushing also signifies ripe time for pollination, aided by such as hummingbirds. Many Tillandsia species are thus naturally hybridized by visiting pollinators or the wind, many new hybridized Tillandsia species and cultivars are products of human growers. Most Tilandsias are adaptive and hardy enough to be grown indoors with adequate lighting and care, many enthusiasts may attach these plants to other objects. Indoor grown Tillandsias generally need to be watered about 1-3 times a week, often by spraying the plant, depending on the species, regular dunking in water may be essential to maintaining their health as well. However, in nature, Airplants get plenty of air movement to help them dry fast enough, for they are susceptible to mold. Some Tillandsia species closely resemble one another, while some tend to form as they mature. Therefore, a displaced pup may be difficult to identify. The genus Tillandsia was named by Carl Linnaeus after the Swedish physician, some common types of Tillandsia include air plant, ball moss and Spanish moss, the latter referring to T. usneoides in particular
31.
Sea
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A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, the sea is the system of Earths salty. The sea moderates Earths climate and has important roles in the cycle, carbon cycle. Although the sea has been traveled and explored since prehistory, the scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. Owing to the present state of continental drift, the Northern Hemisphere is now equally divided between land and sea but the South is overwhelmingly oceanic. Salinity in the ocean is generally in a narrow band around 3. 5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers. About 85% of the solids in the sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature, surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun. The direction of all of these is governed by surface and submarine land masses, former changes in sea levels have left continental shelves, shallow areas in the sea close to land. The most diverse areas surround great tropical coral reefs, whaling in the deep sea was once common but whales dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting. Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earths atmosphere, the sea is an essential aspect of human trade, travel, mineral extraction, and power generation. It is the scene of activities including swimming, diving, surfing. However, population growth, industrialization, and intensive farming have all contributed to marine pollution. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem, both senses of sea date to Old English, the larger sense has required a definite article since Early Middle English. Seas are generally larger than lakes and contain salt water, while the defining elements of size and being bounded are generally used, there is no formally accepted technical definition of sea among oceanographers. In international law, the United Nations Convention on the Law of the Sea states that all the ocean is the sea. Earth is the known planet with seas of liquid water on its surface, although Mars possesses ice caps
32.
Coast
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A coastline or a seashore is the area where land meets the sea or ocean, or a line that forms the boundary between the land and the ocean or a lake. A precise line that can be called a coastline cannot be determined due to the Coastline paradox, the term coastal zone is a region where interaction of the sea and land processes occurs. Both the terms coast and coastal are often used to describe a location or region, for example, New Zealands West Coast. Edinburgh for example is a city on the coast of Scotland, a pelagic coast refers to a coast which fronts the open ocean, as opposed to a more sheltered coast in a gulf or bay. A shore, on the hand, can refer to parts of the land which adjoin any large body of water, including oceans. Similarly, the related term refers to the land alongside or sloping down to a river or to a body of water smaller than a lake. Bank is also used in parts of the world to refer to an artificial ridge of earth intended to retain the water of a river or pond. According to the UN atlas, 44% of people live within 150 kilometres of the sea, tides often determine the range over which sediment is deposited or eroded. Areas with high tidal ranges allow waves to reach farther up the shore, the tidal range is influenced by the size and shape of the coastline. Tides do not typically cause erosion by themselves, however, tidal bores can erode as the waves surge up river estuaries from the ocean. Waves erode coastline as they break on shore releasing their energy, the larger the wave the more energy it releases and the more sediment it moves. Coastlines with longer shores have more room for the waves to disperse their energy, while coasts with cliffs and short shore faces give little room for the wave energy to be dispersed. In these areas the wave energy breaking against the cliffs is higher, sediment deposited by waves comes from eroded cliff faces and is moved along the coastline by the waves. This forms an abrasion or cliffed coast, sediment deposited by rivers is the dominant influence on the amount of sediment located on a coastline. Today riverine deposition at the coast is often blocked by dams and other human regulatory devices, like the ocean which shapes them, coasts are a dynamic environment with constant change. The coast and its adjacent areas on and off shore are an important part of a local ecosystem, Salt marshes and beaches also support a diversity of plants, animals and insects crucial to the food chain. The high level of biodiversity creates a level of biological activity. More and more of the people live in coastal regions
33.
Dry lake
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A dry lake is an ephemeral lakebed, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts, alternative names for the dry lake include alkali flat, alkali sink and playa. A playa lake may cover an area, but it is never deep. Most water in it evaporates, leaving a layer of salt on the surface and these salt covered stretches are called saltpans. The surface of a dry lake is dry, hard and rough during the dry season. Dry lakes are small, round depressions in the surface of the landscape. If its basin is primarily salt, then a dry lake is called a salt pan, pan, hardpan, another dry lake type is the mudflat. Hardpan is the dry terminus of an internally drained basin in a dry climate, the Spanish word playa literally means beach. Dry lakes are known by name in some parts of Mexico. This term is used on the Llano Estacado and other parts of the Southern High Plains. In South America, the term for a dry lake is salar or salina. Pan is the used in most of South Africa. These may include the small round pans, typical of the Chrissiesmeer area, to the extensive pans of the Northern Cape province. It is also used in Australia, distinguished are salt pans and clay pans. In Arabic, a flat is called a sabkha or shott. In Central Asia, a similar cracked mud salt flat is known as a takyr, in Iran salt flats are called kavir. A playa lake is formed when water from rain or other sources, like intersection with a table, flows into a dry depression in the landscape. If the total annual evaporation rate exceeds the annual inflow
34.
Apocynaceae
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Members of the family are native to European, Asian, African, Australian, and American tropics or subtropics, with some temperate members. The family Asclepiadaceae is considered a subfamily of Apocynaceae and contains 348 genera, many species are tall trees found in tropical rainforests, but some grow in tropical dry environments. Also perennial herbs from temperate zones occur, many of these plants have milky latex, and many species are poisonous if ingested. Some genera of Apocynaceae, such as Adenium, have milky latex apart from their sap, the dogbane family includes annual plants, perrenial herbs, stem succulents, woody shrubs, trees, or vines. Most exude a sap with latex, if injured. Leaves are not divided into smaller leaflets, leaves may appear one at a time with each occurrence on alternating sides of the stem, but usually occur in pairs or in whorls. When paired, they occur on opposite sides of the stem, there is no stipule, or stipules are small and sometimes fingerlike. Flowers are usually showy, have radial symmetry, and are born in head that are cymes or racemes and they are perfect, with a synsepalous, five-lobed calyx united into a tube at the base. Five petals are united into a tube with four or five epipetalous stamens, the style is expanded at the apex into a massive clavuncle just below the stigma. The ovary is superior, bicarpellary, and apocarpous, with a common fused style. The fruit is a drupe, a berry, a capsule, as of 2012, the family was described as comprising some 5,100 species, where Apocynoideae, Asclepiadoideae, Periplocoideae, Rauvolfioideae, and Secamonoideae are its five subfamilies. The former family Asclepiadaceae is included in Apocynaceae according to the Angiosperm Phylogeny Group III modern, an updated classification, including 366 genera,25 tribes and 49 subtribes, was published in 2014. Also Asclepias syriaca is an invasive weed, all plant-derived natural products have some inherent toxicity on ingestion, and many are very toxic, even lethal. This is true of many contained in species of plants from the Apocynaceae family, several plants of the Apocynaceae family members have had economic uses in the past. Several are sources of important natural products—pharmacologic tool compounds and drug research candidates, cardiac glycosides, which affect heart function, are a ready example. Members studied and known to have such glycosides include the Acokanthera, Apocynum, Cerbera, Nerium, Thevetia, rauvolfia serpentina synthesizes the alkaloids reserpine and rescinnamine, which are of interest in studies of the treatment of high blood pressure, as well as some forms of psychosis. Catharanthus roseus yields alkaloids studied with regard to the treatment of cancer, certain species of the genus Tabernathe, most notably Tabernathe Iboga contain tryptamine alkaloids such as ibogaine in the roots. Several genera are grown as ornamental plants, including Amsonia, Nerium, Vinca, Carissa, Allamanda, Plumeria, Thevetia, Mandevilla, in addition, the genera Landolphia, Hancornia, Funtumia and Mascarenhasia were used as a commercial source of inferior rubber
35.
Pachypodium lealii
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The Bottle tree is a species of plant included in the genus Pachypodium. The scientific name derives from the 19th century Portuguese geologist Fernando da Costa Leal and this species can be either a shrub or a tree up to 6 meters tall and is characterized by the thick bottle-shaped trunk, which is almost branchless until the top. The branches are few and covered by slender thorns up to 30 cm long, leaves are oblong and are covered with short hairs on both surfaces. The flowers, shown below in detail, are present in the spring, the white flowers, characteristic of the Apocynaceae family, cluster around the tips of the branches. The Bottle tree is a species of Namibia and southern Angola where it occupies the semi-desert areas and dry bushvelds. It is especially common in the Etendeka plateau of NE Namibia, the plant produces a watery latex, rich in toxic alkaloids, used by local populations as arrow poison for hunting. In contact with the eyes this latex can produce blindness, encyclopedia of Life A. van Wyk and P. van Wyk
36.
Asphodelaceae
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Asphodelaceae is a family of flowering plants in the order Asparagales. Until 2016, the name Xanthorrhoeaceae was used for the family in the APG classification system, such a family has been recognized by most taxonomists, but the circumscription has varied widely. In its current circumscription in the APG IV system, it includes about 40 genera and 900 known species, as defined by the Angiosperm Phylogeny Group in 2009, the family consisted of three subfamilies, Asphodeloideae, Hemerocallidoideae and Xanthorrhoeoideae. Earlier these three had been treated as separate families, the family Asphodelaceae has now been proposed to be a nomen conservandum, and the proposal has been recommended for ratification in 2017. In that case, Asphodelaceae will have priority over Xanthorrhoeaceae and this is reflected in the APG IV family lists. The family has a wide, but scattered throughout the tropics. Many of the species are cultivated as ornamentals, a few are grown commercially for cut flowers. Two species of Aloe are grown for their sap, which has medicinal. In some of the systems of plant taxonomy, such as the Cronquist system. Molecular phylogenetic studies have shown that Dasypogonaceae belongs to the commelinids and is not even in the same order as Asphodelaceae. Members of the Asphodelaceae are diverse, with few characters uniting the three currently recognized. The presence of anthraquinones is one common character, the flowers are typically borne on a leafless stalk which arises from a basal rosette of leaves. The individual flowers have jointed stalks, a disk of woody tissue is present at the base of the ovule. The subfamily Xanthorrhoeoideae contains only the genus Xanthorrhoea, native to Australia, plants typically develop thick woody stems, the flowers are arranged in a dense spike. Members of the subfamily Asphodeloideae are often leaf succulents, such as aloes and haworthias, members of the subfamily Hemerocallidoideae are varied in habit. Daylilies are one of the widely grown members of this subfamily, three separate families were at one time recognized, Asphodelaceae, Hemerocallidaceae and Xanthorrhoeaceae. Molecular phylogenetic studies have shown that the three are related, although Rudall considered that the combination into a single clade was not supported by morphological analysis. The most recent APG classification, the APG IV system of 2016, the former families are treated as three subfamilies, Asphodeloideae, Hemerocallidoideae and Xanthorrhoeoideae
37.
Crassula ovata
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Crassula ovata, commonly known as jade plant, friendship tree, lucky plant, or money tree, is a succulent plant with small pink or white flowers. It is native to South Africa and Mozambique, and is common as a houseplant worldwide, much of its popularity stems from the low levels of care needed, the jade plant requires little water and can survive in most indoor conditions. It is sometimes referred to as the tree, however. The jade plant is an evergreen with thick branches and it has thick, shiny, smooth, leaves that grow in opposing pairs along the branches. Leaves are a rich green, although some may appear to be more of a yellow-green. Some varieties may develop a red tinge on the edges of leaves when exposed to levels of sunlight. New stem growth is the color and texture as the leaves. Although becoming brown and appearing woody with age, stems never become true lignified tissue, remaining succulent, under the right conditions, they may produce small white or pink star-like flowers in early spring. Numerous varieties and cultivars have been selected, of which C. ovata Hummels Sunset has gained the Royal Horticultural Societys Award of Garden Merit, Crassula ovata is native to Mozambique and to the Eastern Cape and KwaZulu-Natal provinces of South Africa. As a succulent, Crassula ovata requires little water in the summer, C. ovata may garnish a red tinge around its leaves when grown with bright sunlight. In more extreme cases, the colour of the plant is lost. This is caused by the plant making pigments such as carotenoids to protect from harsh sunlight. The jade plant also does best in rich, well-draining soil, the plant also flowers in the wintertime, particularly during a cooler, darker, dry spell. C. ovata is sometimes attacked by mealybugs, a nuisance of the succulents. The jade plant is known for its ease of propagation. Jade plants propagate readily from both with success rates higher with cuttings, in the wild, propagation is the jade plants main method of reproduction. Branches regularly fall off wild jade plants and these branches may root, like many succulents, jade plants can be propagated from just the swollen leaves which grow in pairs on the stems. While propagation methods may vary, most will follow similar steps, typically, the wounds on the leaves are left to dry and callous over
38.
Euphorbiaceae
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Most spurges such as Euphorbia paralias are herbs, but some, especially in the tropics, are shrubs or trees, such as Hevea brasiliensis. Some, such as Euphorbia canariensis, are succulent and resemble cacti because of convergent evolution and this family occurs mainly in the tropics, with the majority of the species in the Indo-Malayan region and tropical America a good second. A large variety occurs in tropical Africa, but they are not as abundant or varied as in the two other tropical regions. However, Euphorbia also has many species in areas such as the Mediterranean Basin, the Middle East, South Africa. The leaves are alternate, seldom opposite, with stipules and they are mainly simple, but where compound, are always palmate, never pinnate. Stipules may be reduced to hairs, glands, or spines, the plants can be monoecious or dioecious. The radially symmetrical flowers are unisexual, with the male and female usually on the same plant. As can be expected from such a family, a wide variety exists in the structure of the flowers. The stamens number from one to 10, the female flowers are hypogynous, that is, with superior ovaries. The genera in tribe Euphorbieae, subtribe Euphorbiinae show a highly specialized form of pseudanthium called a cyathium and this is usually a small, cup-like involucre consisting of fused-together bracts and peripheral nectary glands, surrounding a ring of male flowers, each a single stamen. In the middle of the stands an female flower, a single pistil with branched stigmas. This whole arrangement resembles a single flower, the fruit is usually a schizocarp, but sometimes a drupe. A typical schizocarp is the regma, a fruit with three or more cells, each of which splits open at maturity into separate parts and then breaks away explosively. The family contains a variety of phytotoxins, mainly diterpene esters, alkaloids, glycosides. A milky latex is a characteristic of the subfamilies Euphorbioideae and Crotonoideae, the latex is poisonous in the Euphorbioideae, but innocuous in the Crotonoideae. White mangrove, or blind-your-eye mangrove latex causes blistering on contact, other common names are milky mangrove, buta buta, and gewa. The latex of spurge was used as a laxative, recent molecular studies have shown that the enigmatic family Rafflesiaceae, which was only recently recognized to belong to order Malpighiales, is derived from within the Euphorbiaceae. The Euphorbiaceae family has about 7,500 species organised into 300 genera,37 tribes, prominent plants include cassava, castor oil plant, Barbados nut, and the Para rubber tree
39.
Euphorbia obesa
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Euphorbia obesa is a subtropical succulent species of Euphorbia genus. It comes from South Africa, especially in the Cape Province, in the wild, it is endangered because of over-collection and poaching, because of its slow growth, and the fact that the pod contains only 2 to 3 seeds. However, it is cultivated in botanical gardens. Euphorbia obesa resembles a ball, thornless and decorative and it is commonly known as baseball plant due to its shape. Its diameter is between 6 cm and 15 cm depending on its age, young Euphorbia obesas are spherical, but become cylindrical with age. They contain water reservoirs for periods of drought and it almost always shows 8 ridges adorned with small deep gibbosity regularly planted on the edges. It is green with lighter or darker stripes. In the wild, and with exposure to sunlight, it shows red. The plant is dioecious, which means that a subject has only male or female flowers, the small flowers are insignificant in apex. In fact, like all Euphorbia, flowers are called cyathia, as in all Euphorbia species, the latex is toxic. Living in similar conditions on two different continents, Euphorbia obesa presents a form of convergence with Astrophytum asterias which is a cactus from Mexico and this species is indigenous to a small range in the arid Karoo region of South Africa. This is a region of summer rainfall
40.
Cylindropuntia imbricata
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The cane cholla is a cactus found in the Southwestern United States and northern Mexico, including some cooler regions in comparison to many other cacti. It occurs primarily in the regions of the Southwestern United States in the states of Oklahoma, Texas, New Mexico, Arizona. It is often conspicuous because of its shrubby or even size, its silhouette. The cane chollas range is the regions of Nevada, Arizona, New Mexico, Oklahoma, and Texas, south to Durango, Zacatecas. It occurs at altitudes from 1,200 to 2,300 m and is hardy for a cactus, plants may form thickets or be spaced at a few times their width in gardens. The species is naturalised in Australia in old mining localities and along watercourses and it is known there by the common names of Devils rope cactus or Devils rope pear. It is a noxious weed in New South Wales and also occurs in Queensland, Victoria. The above-ground part consists of much-branched cylindrical stems, the end joints being about 3 cm in diameter, the joints, unlike those of some chollas, are hard to detach. The stems are highly tubercular with a pattern of long oval lumps, a typical height is about 1 m, but exceptionally it can grow to 4.6 m with a trunk diameter of 25 cm. The width is similar to or somewhat greater than the height. The stems are armed with clusters of up to about 10 red to pink spines, the stems and fruits also have many spines or glochids about 1 mm long that can detach and stick in the skin. Plagiotropic stems grow in a star- or crown-like pattern around a central orthotropic stem and this species blooms in late spring or early summer. The flowers are purple or magenta, rarely rose-pink, about 5 cm wide. The fruits are yellowish, tubercular like the stems, and shaped something like the frustum of a cone, with a hollow at the end where the flower fell off. The plant retains them all winter and they are dry and not tasty, though the Indians of Arizona and New Mexico are said to have eaten them. In addition to sexual reproduction, the tree cholla reproduces when stem joints fall to the ground, thus this species spreads and its spread is hard to control, especially where animals defecate seeds and carry stem joints stuck to their hide some distance from the parent plant. Waves of invasion typically occur four or five years after drought combined with grazing, the fruits are also eaten by various wild birds and mammals, including pronghorn, desert bighorn sheep, and deer. The thorny plants provide escape for cover for small animals
41.
Malvaceae
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Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of this family include okra, cotton, and cacao, the largest genera in terms of number of species include Hibiscus, Sterculia, Dombeya, Pavonia and Sida. The circumscription of the Malvaceae is controversial, the traditional Malvaceae sensu stricto comprise a very homogeneous and cladistically monophyletic group. s. are not monophyletic groups. Thus, the Malvaceae can be expanded to all of these families so as to compose a monophyletic group. Adopting this circumscription, the Malvaceae incorporate a larger number of genera. This article is based on the circumscription, as presented by the Angiosperm Phylogeny Website. The Malvaceae s. l. comprise nine subfamilies, a tentative cladogram of the family is shown below. The diamond denotes a poorly supported branching, if looking for information about the traditional Malvaceae s. s. we recommend referring to Malvoideae, the subfamily that approximately corresponds to that group. The English common name comes from Latin malva. Malva itself was derived from the word for the plant in ancient Mediterranean languages. Cognates of the word include Ancient Greek μαλάχη or μολόχη, Modern Greek μολόχα, modern Arabic, ملوخية and modern Hebrew, most species are herbs or shrubs, but some are trees and lianas. Leaves are generally alternate, often lobed or compound and palmately veined. The margin may be entire, but when dentate, a vein ends at the tip of each tooth, the stems contain mucous canals and often also mucous cavities. Hairs are common, and are most typically stellate, the flowers are commonly borne in definite or indefinite axillary inflorescences, which are often reduced to a single flower, but may also be cauliflorous, oppositifolious, or terminal. They can be unisexual or bisexual, and are actinomorphic, often associated with conspicuous bracts. They generally have five sepals, most frequently basally connate. The stamens are five to numerous, and connate at least at their bases, the pistils are composed of two to many connate carpels. The ovary is superior, with axial placentation, with capitate or lobed stigma, the flowers have nectaries made of many tightly packed glandular hairs, usually positioned on the sepals
42.
Adansonia digitata
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Adansonia digitata is the most widespread of the Adansonia species, and is native to the African continent. The long-lived pachycauls are typically found in dry, hot savannahs of sub-Saharan Africa, where they dominate the landscape, and reveal the presence of a watercourse from afar. Their growth rate is determined by water or rainfall, and their maximum age. They have traditionally been valued as sources of food, water, health remedies or places of shelter and are steeped in legend, explorers of old were inclined to carve their names on baobabs, and many are defaced by modern graffiti. Common names for the baobab include dead-rat tree, monkey-bread tree, upside-down tree, the vernacular name baobab is derived from Arabic بو حِباب, which means father of many seeds. The scientific name Adansonia refers to the French explorer and botanist, Michel Adanson, when Théodore Monod searched the island in the 20th century, the tree was not to be found however. Adanson concluded that the baobab, of all the trees he studied, “is probably the most useful tree in all. ”He consumed baobab juice twice a day and he remained convinced that it maintained his health for him. Digitata refers to the digits of the hand, the baobabs compound leaves with normally five leaflets are akin to a hand. The trees usually grow as solitary individuals, and are large, some large individuals live to well over a thousand years of age. All baobab trees are deciduous, losing their leaves in the dry season and they can grow to between 5–25 m in height. They are in fact known both for their height and trunks girth, the trunk tends to be bottle-shaped and can reach a diameter of 10–14 m. The span of the roots actually exceed the height, a factor that enables it to survive in a dry climate. Many consider the tree to be due to the trunk likeness to a taproot. The trunk is smooth and shiny and can range from being reddish brown to grey, the branches are thick and wide and very stout compared to the trunk. During the early summer the tree bears very large, heavy and these are 12 cm across and open during the late afternoon to stay open for one night. The pendulous, showy flowers have a large number of stamens. They have a sweet scent but later emit a smell, especially when they turn brown. Researchers have shown that they appear to be pollinated by fruit bats of the subfamily Pteropodinae
43.
Moringa
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Moringa, native to parts of Africa and Asia, is the sole genus in the flowering plant family Moringaceae. The name is derived from murungai/munakkai/muringa, the Tamil/Telugu/Malayalam word for drumstick and it contains 13 species from tropical and subtropical climates that range in size from tiny herbs to massive trees. The most widely cultivated species is Moringa oleifera, a tree native to the foothills of the Himalayas in northwestern India. M. stenopetala, an African species, is widely grown. Moringa species grow quickly in many types of environments, Moringa borziana Mattei Moringa concanensis Nimmo Moringa drouhardii Jum. – bottle tree Moringa hildebrandtii Engl. – Hildebrandts moringa Moringa longituba Engl, Moringa oleifera Lam. – horseradish tree Moringa ovalifolia Dinter & Berger Moringa peregrina Fiori indigenous to Horn of Africa and in the Southern Sinai, Egypt Moringa pygmaea Verdc. Moringa Home Page, Instituto de Biología, Universidad Nacional Autónoma de México The International Moringa Germplasm Collection
44.
Asparagaceae
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Asparagaceae is a family of flowering plants, placed in the order Asparagales of the monocots. In earlier classification systems, the species involved were often treated as belonging to the family Liliaceae, the revised APG III system of 2009 allows only the broader sense. A paper published at the time proposed seven subfamilies to correspond to the originally separate families. Unless otherwise noted, the alphabetical list below is based on genera accepted by the World Checklist of Selected Plant Families as in the family Asparagaceae, the reference against the subfamily name is to the source which places the genus in that subfamily. Asparagaceae in L. Watson and M. J. Dallwitz, the families of flowering plants, descriptions, illustrations, identification, information retrieval. Https, //web. archive. org/web/20070103200438/http, //delta-intkey. com, 80/ Liliaceae in Flora of North America NCBI Taxonomy Browser links at CSDL, Texas
