Arabidopsis thaliana, the thale cress, mouse-ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa. A. thaliana is considered a weed. A winter annual with a short life cycle, A. thaliana is a popular model organism in plant biology and genetics. For a complex multicellular eukaryote, A. thaliana has a small genome of 135 megabase pairs. It was the first plant to have its genome sequenced, is a popular tool for understanding the molecular biology of many plant traits, including flower development and light sensing. Arabidopsis thaliana is an annual plant growing to 20–25 cm tall; the leaves form a rosette at the base of the plant, with a few leaves on the flowering stem. The basal leaves are green to purplish in color, 1.5–5 cm long and 2–10 mm broad, with an entire to coarsely serrated margin. Leaves are covered with unicellular hairs; the flowers are 3 mm in diameter, arranged in a corymb. The fruit is a siliqua 5 -- 20 mm long. Roots are simple in structure, with a single primary root that grows vertically downward producing smaller lateral roots.
These roots form interactions with rhizosphere bacteria such as Bacillus megaterium. A. thaliana can complete its entire lifecycle in six weeks. The central stem that produces flowers grows after about three weeks, the flowers self-pollinate. In the lab, A. thaliana may be grown in Petri plates, pots, or hydroponics, under fluorescent lights or in a greenhouse. The plant was first described in 1577 in the Harz Mountains by Johannes Thal, a physician from Nordhausen, Thüringen, who called it Pilosella siliquosa. In 1753, Carl Linnaeus renamed the plant Arabis thaliana in honor of Thal. In 1842, the German botanist Gustav Heynhold erected the new genus Arabidopsis and placed the plant in that genus; the genus name, comes from Greek, meaning "resembling Arabis". Thousands of natural inbred accessions of A. thaliana have been collected from throughout its natural and introduced range. These accessions exhibit considerable genetic and phenotypic variation which can be used to study the adaptation of this species to different environments.
A. thaliana is native to Europe, Asia and human observations indicate its geographic distribution is rather continuous from the Mediterranean to Scandinavia and Spain to Greece. It appears to be native in tropical alpine ecosystems in Africa and South Africa, it has been introduced and naturalized worldwide, including in North America ca. the 17th century. A. Thaliana grows and pioneers rocky and calcareous soils, it is considered a weed, due to its widespread distribution in agricultural fields, railway lines, waste ground and other disturbed habitat, but due to its limited competitive ability and small size it is not categorized as a noxious weed. Like most Brassicaceae species, A. thaliana is edible by humans as a salad or cooked, but it does not enjoy a widespread use as a spring vegetable. Botanists and biologists began to research A. thaliana in the early 1900s, the first systematic description of mutants was done around 1945. A. thaliana is now used for studying plant sciences, including genetics, population genetics, plant development.
Although A. thaliana has little direct significance for agriculture, it has several traits that make it a useful model for understanding the genetic and molecular biology of flowering plants. The first mutant in A. thaliana was documented in 1873 by Alexander Braun, describing a double flower phenotype. However, not until 1943 did Friedrich Laibach propose A. thaliana as a model organism. His student, Erna Reinholz, published her thesis on A. thaliana in 1945, describing the first collection of A. thaliana mutants that they generated using X-ray mutagenesis. Laibach continued his important contributions to A. thaliana research by collecting a large number of accessions. With the help of Albert Kranz, these were organised into a large collection of 750 natural accessions of A. thaliana from around the world. In the 1950s and 1960s, John Langridge and George Rédei played an important role in establishing A. thaliana as a useful organism for biological laboratory experiments. Rédei wrote several scholarly reviews instrumental in introducing the model to the scientific community.
The start of the A. thaliana research community dates to a newsletter called Arabidopsis Information Service, established in 1964. The first International Arabidopsis Conference was held in Göttingen, Germany. In the 1980s, A. thaliana started to become used in plant research laboratories around the world. It was one of several candidates that included maize and tobacco; the latter two were attractive, since they were transformable with the then-current technologies, while maize was a well-established genetic model for plant biology. 1986 was a breakthrough year for A. thaliana as a model plant, in which T-DNA-mediated transformation and the first cloned A. thaliana gene were described. The small size of its genome, the fact that it is diploid, makes Arabidopsis thaliana useful for genetic mapping and sequencing — with about 135 mega base pairs and five chromosomes, A. thaliana has one of the smallest genomes among plants. It was long thought to have the small
A bean is a seed of one of several genera of the flowering plant family Fabaceae, which are used for human or animal food. The word "bean" and its Germanic cognates have existed in common use in West Germanic languages since before the 12th century, referring to broad beans and other pod-borne seeds; this was long. After Columbian-era contact between Europe and the Americas, use of the word was extended to pod-borne seeds of Phaseolus, such as the common bean and the runner bean, the related genus Vigna; the term has long been applied to many other seeds of similar form, such as Old World soybeans, chickpeas, other vetches, lupins, to those with slighter resemblances, such as coffee beans, vanilla beans, castor beans, cocoa beans. Thus the term "bean" in general usage can mean a host of different species. Seeds called "beans" are included among the crops called "pulses", although a narrower prescribed sense of "pulses" reserves the word for leguminous crops harvested for their dry grain; the term bean excludes legumes with tiny seeds and which are used for forage and silage purposes.
According to the United Nations Food and Agriculture Organization the term "BEANS, DRY" should include only species of Phaseolus. One is that in the past, several species, including Vigna angularis, mungo and aconitifolia, were classified as Phaseolus and reclassified. Another is that it is not surprising that the prescription on limiting the use of the word, because it tries to replace the word's older senses with a newer one, has never been followed in general usage. Unlike the related pea, beans are a summer crop that need warm temperatures to grow. Maturity is 55–60 days from planting to harvest; as the bean pods mature, they turn yellow and dry up, the beans inside change from green to their mature colour. As a vine, bean plants need external support, which may be provided in the form of special "bean cages" or poles. Native Americans customarily grew them along with corn and squash, with the tall cornstalks acting as support for the beans. In more recent times, the so-called "bush bean" has been developed which does not require support and has all its pods develop simultaneously.
This makes the bush bean more practical for commercial production. Beans are one of the longest-cultivated plants. Broad beans called fava beans, in their wild state the size of a small fingernail, were gathered in Afghanistan and the Himalayan foothills. In a form improved from occurring types, they were grown in Thailand since the early seventh millennium BCE, predating ceramics, they were deposited with the dead in ancient Egypt. Not until the second millennium BCE did cultivated, large-seeded broad beans appear in the Aegean and transalpine Europe. In the Iliad is a passing mention of beans and chickpeas cast on the threshing floor. Beans were an important source of protein throughout Old and New World history, still are today; the oldest-known domesticated beans in the Americas were found in Guitarrero Cave, an archaeological site in Peru, dated to around the second millennium BCE. However, genetic analyses of the common bean Phaseolus shows that it originated in Mesoamerica, subsequently spread southward, along with maize and squash, traditional companion crops.
Most of the kinds eaten fresh or dried, those of the genus Phaseolus, come from the Americas, being first seen by a European when Christopher Columbus, during his exploration of what may have been the Bahamas, found them growing in fields. Five kinds of Phaseolus beans were domesticated by pre-Columbian peoples: common beans grown from Chile to the northern part of what is now the United States, lima and sieva beans, as well as the less distributed teparies, scarlet runner beans and polyanthus beans One famous use of beans by pre-Columbian people as far north as the Atlantic seaboard is the "Three Sisters" method of companion plant cultivation: In the New World, many tribes would grow beans together with maize, squash; the corn would not be planted in rows as is done by European agriculture, but in a checkerboard/hex fashion across a field, in separate patches of one to six stalks each. Beans would be planted around the base of the developing stalks, would vine their way up as the stalks grew.
All American beans at that time were vine plants, "bush beans" having been bred only more recently. The cornstalks would work as a trellis for the beans, the beans would provide much-needed nitrogen for the corn. Squash would be planted in the spaces between the patches of corn in the field, they would be provided slight shelter from the sun by the corn, would shade the soil and reduce evaporation, would deter many animals from attacking the corn and beans because their coarse, hairy vines and broad, stiff leaves are difficult or uncomfortable for animals such as deer and raccoons to walk through, crows to land on, etc. Dry beans come from both Old World varieties of New World varieties. Beans are a heliotropic plant. At night, they go into a folded "sleep" position; the world genebanks hold about 40,000 bean varieties, although on
Hardiness of plants describes their ability to survive adverse growing conditions. It is limited to discussions of climatic adversity, thus a plant's ability to tolerate cold, drought, flooding, or wind are considered measurements of hardiness. Hardiness of plants is defined by their native extent's geographic location: longitude and elevation; these attributes are simplified to a hardiness zone. In temperate latitudes, the term most describes resistance to cold, or "cold-hardiness", is measured by the lowest temperature a plant can withstand. Hardiness of a plant is divided into two categories: tender, hardy; some sources use the erroneous terms "Half-hardy" or "Fully hardy". Tender plants are those killed by freezing temperatures, while hardy plants survive freezing—at least down to certain temperatures, depending on the plant. "Half-hardy" is a term used sometimes in horticulture to describe bedding plants which are sown in heat in winter or early spring, planted outside after all danger of frost has passed.
"Fully hardy" refers to plants being classified under the Royal Horticultural Society classifications, can cause confusion to those not using this method. Plants vary a lot in their tolerance of growing conditions; the selective breeding of varieties capable of withstanding particular climates forms an important part of agriculture and horticulture. Plants adapt to changes in climate on their own to some extent. Part of the work of nursery growers of plants consists of cold hardening, or hardening off their plants, to prepare them for conditions in life. Winter-hardy plants grow during the winter, or at least remain dormant. Apart from hardy evergreens, these include many cultivated plants, including varieties of cabbage and broccoli, all kinds of carrot; some bulbs – such as tulips – need cold winters to bloom, while others – such as freesia – can survive a freezing winter. Many domestic plants are assigned a hardiness zone that specifies the climates in which they can survive. Winter gardens are dependent upon the cultivation of winter-hardy plants.
Woody plants survive freezing temperatures by suppressing the formation of ice in living cells or by allowing water to freeze in plant parts that are not affected by ice formation. The common mechanism for woody plants to survive up to –40 °C is supercooling. Woody plants that survive lower temperatures are dehydrating their cells, allowing water to freeze between cell walls and the cells to survive. Plants considered hardy may not survive freezing if they are not acclimated, which renders them unable to use these mechanisms. Various hardiness ratings are published. In the USA, the most used is the USDA system of hardiness zones based on average minimum yearly temperatures; this system was developed for the diverse range of conditions in the United States, from baking desert to frozen tundra. Another used system is the Sunset Climate Zone system; this system is less dependent on the yearly minimum. In contrast the United Kingdom and Western Europe have an oceanic climate, experience a narrower range of temperatures, tempered by the presence of the Gulf Stream.
This results in areas like western Scotland experiencing mild winter conditions that enable the growing of subtropical plants, despite being well to the north of subtropical climate areas. The Royal Horticultural Society has published a set of hardiness ratings applicable to the UK; the ratings range from H1a to H7. H1a, higher than 15 °C, applies to tropical plants permanently under glass in heat. Most outdoor plants in the UK fall within the range H4, −10 to −5 °C to H5, −15 to −10 °C; the average minimum temperature in the UK is much warmer than the average minimums in most of the US. This means that the coldest areas in the UK would be considered USDA Zone 7, plants considered'Fully Hardy' in the UK may not be hardy below Zone 7 in the US. In addition to cold tolerance, plant hardiness has been observed to be linked to how much stress specific plants are undergoing into the winter, or how fast the onset of cold weather is in a specific year; this means that stressed plants will exhibit less cold tolerance than plants that have been well maintained.
Plants may die if the winter changes from balmy to exceptionally cold in a short period of time. Hardiness zone Microclimate Interactive Version of the 1990 USDA Hardiness Zone Map
Tagetes is a genus of annual or perennial herbaceous plants in the sunflower family. It was described as a genus by Linnaeus in 1753; the genus is native to North and South America, but some species have become naturalized around the world. One species, T. minuta, is considered a noxious invasive plant in some areas. Tagetes species vary in size from 0.1 to 2.2 m tall. Most species have pinnate green leaves. Blooms occur in golden, orange and white colors with maroon highlights. Floral heads are to 4–6 cm diameter with both ray florets and disc florets. In horticulture, they tend to be planted as annuals, although the perennial species are gaining popularity, they have fibrous roots. Depending on the species, Tagetes species grow well in any sort of soil. Most horticultural selections grow best in soil with good drainage though some cultivars are known to have good tolerance to drought. Shores, springs, quiet waters in streams, wetlands, wet meadows, waterside swamps and meadows which are prone to flooding, damp hollows in broad-leaved forests, snow-bed sites, sometimes underwater.
The name Tagetes is from the name of the Etruscan Tages, born from the plowing of the earth. It refers to the ease with which plants of this genus come out each year either by the seeds produced in the previous year, or by the stems which regrow from the stump in place; the common name in English, "marigold", is derived from "Mary's gold", a name first applied to a similar plant native to Europe, Calendula officinalis. The most cultivated varieties of Tagetes are known variously as African marigolds, or French marigolds; the so-called signet marigolds are hybrids derived from Tagetes tenuifolia. Depending on the species, marigold foliage has a musky, pungent scent, though some varieties have been bred to be scentless, it is said to deter some common insect pests, as well as nematodes. Tagetes species are hence used in companion planting for tomato, chili pepper and potato. Due to antibacterial thiophenes exuded by the roots, Tagetes should not be planted near any legume crop; some of the perennial species are rodent - and javalina or peccary-resistant.
T. Minuta from South America, has been used as a source of essential oil for the perfume and industry known as tagette or "marigold oil", as a flavourant in the food and tobacco industries, it is cultivated in South Africa, where the species is a useful pioneer plant in the reclamation of disturbed land. The florets of Tagetes erecta are rich in the orange-yellow carotenoid lutein and are used as a food colour in the European Union for foods such as pasta, vegetable oil, mayonnaise, salad dressing, baked goods, dairy products, ice cream, citrus juice and mustard. In the United States, the powders and extracts are only approved as colorants in poultry feed. Marigolds are recorded as a food plant for some Lepidoptera caterpillars including the dot moth, a nectar source for other butterflies, they are part of butterfly gardening plantings. In the wild, many species are pollinated by beetles; the species Tagetes lucida, known as pericón, is used to prepare a sweetish, anise-flavored medicinal tea in Mexico.
It is used as a culinary herb in many warm climates, as a substitute for tarragon, offered in the nursery as "Texas tarragon" or "Mexican mint marigold". Tagetes minuta, native to southern South America, is a tall, upright marigold plant with small flowers used as a culinary herb in Peru and parts of Chile and Bolivia, where it is called by the Incan term huacatay; the paste is used to make the popular potato dish called ocopa. Having both "green" and "yellow/orange" notes, the taste and odor of fresh T. minuta is like a mixture of sweet basil, tarragon and citrus. It is used as a medicinal tea in some areas; the marigold was regarded as the flower of the dead in pre-Hispanic Mexico, parallel to the lily in Europe, is still used in the Day of the Dead celebrations. The marigold is significant in Nepalese culture, where marigold garlands are used in every household during the Tihar festival, it is always sold in the markets for daily rituals. The marigold is widely cultivated in India and Thailand the species T. erecta, T. patula, T. tenuifolia.
Vast quantities of marigolds are used in garlands and decoration for weddings and religious events. Marigold cultivation is extensively seen in Telangana, Andhra Pradesh, Tamil Nadu, West Bengal and Uttar Pradesh states of India. In Ukraine, chornobryvtsi are regarded as one of the national symbols, are mentioned in songs and tales. Accepted species Marigold Commercial Greenhouse Production Growing African Marigolds
Stellaria media, chickweed, is an annual flowering plant in the carnation family Caryophyllaceae. It is native to Europe, but naturalized in many parts of North America, it is used as a cooling herbal remedy, grown as a vegetable crop and ground cover for both human consumption and poultry. It is sometimes called common chickweed to distinguish it from other plants called chickweed. Other common names include chickenwort, maruns, winterweed; the plant germinates in autumn or late winter forms large mats of foliage. The plants are annual and with weak slender stems, they reach a length up to 40 cm. Sparsely hairy, with hairs in a line along the stem; the leaves are the lower ones with stalks. Flowers are white and small with 5 deeply lobed petals; the stamens are 3 and the styles 3. The flowers are followed by the seed pods; this plant sets seed at the same time. Stellaria media is widespread in North America and Asia. There are several related plants referred to as chickweed, but which lack the culinary properties of plants in the genus Stellaria.
Plants in the genus Cerastium are similar in appearance to Stellaria and are in the same family. Stellaria has fine hairs on the sepals. Other members of the family Caryophyllaceae which resemble Stellaria have hairs uniformly covering the entire stem, it has 3 styles, 3-5 8 stamens, variously stated as 8 stamens by Keble Martin and 3 by Clapham and Warburg. Common in lawns, waste places and open areas; the larvae of the European moth yellow shell, of North American moths pale-banded dart or dusky cutworm or North American butterfly dainty sulphur all feed on chickweed. In both Europe and North America this plant is common in gardens and disturbed grounds where it grows as a ground cover. Stellaria media is edible and nutritious, is used as a leaf vegetable raw in salads, it is one of the ingredients of the symbolic dish consumed in the Japanese spring-time festival, Nanakusa-no-sekku. Stellaria media contains plant chemicals known as saponins, which can be toxic to some species when consumed in large quantities.
Chickweed has been known to cause saponin poisoning in cattle. However, as the animal must consume several kilos of chickweed in order to reach a toxic level, such deaths are rare; the plant is used in folk medicine. It has been used as a remedy to treat pulmonary diseases. 17th century herbalist John Gerard recommended it as a remedy for mange. Modern herbalists prescribe it for iron-deficiency anemia, as well as for skin diseases, rheumatic pains and period pain. Not all of these uses are supported by scientific evidence; the plant was used by the Ainu for aching bones. Stems were steeped in hot water before being applied externally to affected areas; the anthraquinones emodin and questin, the flavonoid kaempferol-3,7-O-α-L-dirhamnoside, the phytosterols β-sitosterol and daucosterol, the fatty alcohol 1-hexacosanol can be found in S. media. Other flavonoid constituents are apigenin 6-C-beta-D-galactopyranosyl-8-C-alpha-L-arabinopyranoside, apigenin 6-C-alpha-L-arabinopyranosyl-8-C-beta-D-galactopyranoside, apigenin 6-C-beta-D-galactopyranosyl-8-C-beta-L-arabinopyranoside, apigenin 6-C-beta-D-glucopyranosyl-8-C-beta-D-galactopyranoside, apigenin 6, 8-di-C-alpha-L-arabinopyranoside.
The plant contains triterpenoid saponins of the hydroxylated oleanolic acid type. Proanthocyanidins are present in the testa of seeds. Stellaria is derived from the word'stellar' meaning'star', a reference to the shape of its flowers. Media is derived from Latin and means'between','intermediate', or'mid-sized'. Nanakusa-no-sekku Everitt, J. H.. L.. R.. Weeds in South Texas and Northern Mexico. Lubbock: Texas Tech University Press. ISBN 0-89672-614-2 Tilford, Gregory L.. Edible and Medicinal Plants of the West. Mountain Press Publishing Company. ISBN 0-87842-359-1
Parsley or garden parsley is a species of flowering plant in the family Apiaceae, native to the central Mediterranean region, but has naturalized elsewhere in Europe, is cultivated as a herb, a spice, a vegetable. Where it grows as a biennial, in the first year, it forms a rosette of tripinnate leaves, 10–25 cm long, with numerous 1–3 cm leaflets and a taproot used as a food store over the winter. In the second year, it grows a flowering stem with sparser leaves and umbels with yellow to yellowish-green flowers. Parsley is used in European, Middle Eastern, American cuisine. Curly leaf parsley is used as a garnish. In central Europe, eastern Europe, southern Europe, as well as in western Asia, many dishes are served with fresh green chopped parsley sprinkled on top. Flat leaf parsley is similar, but it is easier to cultivate, some say it has a stronger flavor. Root parsley is common in central and southern European cuisines, where it is used as a snack or a vegetable in many soups and casseroles.
The word "parsley" is a merger of Old English petersilie and the Old French peresil, both derived from Medieval Latin petrosilium, from Latin petroselinum, the latinization of the Greek πετροσέλινον, "rock-celery", from πέτρα, "rock, stone", + σέλινον, "celery". Mycenaean Greek se-ri-no, in Linear B, is the earliest attested form of the word selinon. Garden parsley is a bright green, biennial plant in temperate climates, or an annual herb in subtropical and tropical areas. Where it grows as a biennial, in the first year, it forms a rosette of tripinnate leaves 10–25 cm long with numerous 1–3 cm leaflets, a taproot used as a food store over the winter. In the second year, it grows a flowering stem to 75 cm tall with sparser leaves and flat-topped 3–10 cm diameter umbels with numerous 2 mm diameter yellow to yellowish-green flowers; the seeds are ovoid, 2–3 mm long, with prominent style remnants at the apex. One of the compounds of the essential oil is apiol; the plant dies after seed maturation.
Parsley is a source of flavonoids and antioxidants luteolin, folic acid, vitamin K, vitamin C, vitamin A. Half a tablespoon of dried parsley contains about 6.0 µg of lycopene and 10.7 µg of alpha carotene as well as 82.9 µg of lutein+zeaxanthin and 80.7 µg of beta carotene. Excessive consumption of parsley should be avoided by pregnant women. Normal food quantities are safe for pregnant women, but consuming excessively large amounts may have uterotonic effects. Parsley grows best in well-drained soil, with full sun, it grows best between 22–30 °C, is grown from seed. Germination is slow, taking four to six weeks, it is difficult because of furanocoumarins in its seed coat. Plants grown for the leaf crop are spaced 10 cm apart, while those grown as a root crop are spaced 20 cm apart to allow for the root development. Parsley attracts several species of wildlife; some swallowtail butterflies use parsley as a host plant for their larvae. Bees and other nectar-feeding insects visit the flowers. Birds such as the goldfinch feed on the seeds.
In cultivation, parsley is subdivided into several cultivar groups, depending on the form of the plant, related to its end use. These are treated as botanical varieties, but they are cultivated selections, not of natural botanical origin; the two main groups of parsley used as herbs are curly leaf. Of these, the neapolitanum group more resembles the natural wild species. Flat-leaved parsley is preferred by some gardeners as it is easier to cultivate, being more tolerant of both rain and sunshine, is said to have a stronger flavor — although this is disputed — while curly leaf parsley is preferred by others because of its more decorative appearance in garnishing. A third type, sometimes grown in southern Italy, has thick leaf. Another type of parsley is grown as the Hamburg root parsley; this type of parsley produces much thicker roots than types cultivated for their leaves. Although used in Britain and the United States, root parsley is common in central and eastern European cuisine, where it is used in soups and stews, or eaten raw, as a snack.
Although root parsley looks similar to the parsnip, among its closest relatives in the family Apiaceae, its taste is quite different. Parsley is used in Middle Eastern, European and American cooking. Curly leaf parsley is used as a garnish. Green parsley is used as a garnish on potato dishes, on rice dishes, on fish, fried chicken, lamb and steaks, as well in meat or vegetable stews. In central Europe, eastern Europe, southern Europe, as well as in western Asia, many dishes are served with fresh green, chopped parsley sprinkled on top. In southern and central Europe, parsley is part of bouquet garni, a bundle of fresh herbs used as an ingredient in stocks and sauces. Freshly chopped green parsley is used as a topping for soups such as chicken soup, green salads, or s
A perennial plant or perennial is a plant that lives more than two years. Some sources cite perennial plants being plants; the term is used to differentiate a plant from shorter-lived annuals and biennials. The term is widely used to distinguish plants with little or no woody growth from trees and shrubs, which are technically perennials. Perennials small flowering plants, that grow and bloom over the spring and summer, die back every autumn and winter, return in the spring from their rootstock, are known as herbaceous perennials. However, depending on the rigors of local climate, a plant, a perennial in its native habitat, or in a milder garden, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings or from divisions. Tomato vines, for example, live several years in their natural tropical/subtropical habitat but are grown as annuals in temperate regions because they don't survive the winter. There is a class of evergreen, or non-herbaceous, including plants like Bergenia which retain a mantle of leaves throughout the year.
An intermediate class of plants is known as subshrubs, which retain a vestigial woody structure in winter, e.g. Penstemon; the local climate may dictate whether plants are treated as perennials. For instance, many varieties of Fuchsia are shrubs in warm regions, but in colder temperate climates may be cut to the ground every year as a result of winter frosts; the symbol for a perennial plant, based on Species Plantarum by Linnaeus, is, the astronomical symbol for the planet Jupiter. Perennial plants can be short-lived or they can be long-lived, as are some woody plants like trees, they include a wide assortment of plant groups from ferns and liverworts to the diverse flowering plants like orchids and grasses. Plants that flower and fruit only once and die are termed monocarpic or semelparous. However, most perennials are polycarpic. Perennials grow structures that allow them to adapt to living from one year to the next through a form of vegetative reproduction rather than seeding; these structures include bulbs, woody crowns, rhizomes plus others.
They might have specialized stems or crowns that allow them to survive periods of dormancy over cold or dry seasons during the year. Annuals produce seeds to continue the species as a new generation while the growing season is suitable, the seeds survive over the cold or dry period to begin growth when the conditions are again suitable. Many perennials have developed specialized features that allow them to survive extreme climatic and environmental conditions; some have adapted to survive cold temperatures. Those plants tend to invest a lot of resource into their adaptations and do not flower and set seed until after a few years of growth. Many perennials produce large seeds, which can have an advantage, with larger seedlings produced after germination that can better compete with other plants; some annuals produce many more seeds per plant in one season, while some perennials are not under the same pressure to produce large numbers of seeds but can produce seeds over many years. Dividing perennial plants is something that gardeners do around the months of October.
The point of doing the division at this time is to allow 6 weeks for adequate root growth prior to the ground reaching a freezing temperature. Due to the leaves falling from trees, as well as the excessive amount of rain received in most places during the fall weeks, the ground has adequate moisture for rapid growth; each type of plant must be separated differently. However, plants such as Irises have a root system known as a Rhizomes, these root systems should be planted with the bulb of the plant just above ground level, with leaves from the following year showing; the point of dividing perennials is to increase the amount of a single breed of plant in your garden. The more you divide your perennial plants every year, the more vast your garden will grow. In warmer and more favorable climates, perennials grow continuously. In seasonal climates, their growth is limited to the growing season. In some species, perennials retain their foliage all year round. Other plants are deciduous perennials, for example, in temperate regions a perennial plant may grow and bloom during the warm part of the year, with the foliage dying back in the winter.
In many parts of the world, seasonality is expressed as wet and dry periods rather than warm and cold periods, deciduous perennials lose their leaves in the dry season. With their roots protected below ground in the soil layer, perennial plants are notably tolerant of wildfire. Herbaceous perennials are able to tolerate the extremes of cold in temperate and Arctic winters, with less sensitivity than trees or shrubs. Perennial plants can be differentiated from annuals and biennials in that perennials have the ability to remain dormant over long periods of time and continue growth and reproduction; the meristem of perennial plants communicates with the hormones produced due to environmental situations and stage of development to begin and halt the ability to grow or flower. There is a distinction between the ability to grow and actual task of growth. For example, most trees regain the ability to grow in the midst of winter but do not initiate physical growth until the spring and summer months.
The start of dormancy can be seen in perennials pla