A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant; the embryo is developed from the seed coat from the integuments of the ovule. Seeds have been an important development in the reproduction and success of gymnosperm and angiosperm plants, relative to more primitive plants such as ferns and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates; the term "seed" has a general meaning that antedates the above – anything that can be sown, e.g. "seed" potatoes, "seeds" of corn or sunflower "seeds". In the case of sunflower and corn "seeds", what is sown is the seed enclosed in a shell or husk, whereas the potato is a tuber.
Many structures referred to as "seeds" are dry fruits. Plants producing berries are called baccate. Sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits have a hardened fruit layer fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut. Seeds are produced in several related groups of plants, their manner of production distinguishes the angiosperms from the gymnosperms. Angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds for protection in order to secure healthy growth; some fruits have layers of both fleshy material. In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by the cone scales.
Seed production in natural plant populations varies from year to year in response to weather variables and diseases, internal cycles within the plants themselves. Over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, nine good seed crops, when evaluated for production of adequate seedlings for natural forest reproduction. Angiosperm seeds consist of three genetically distinct constituents: the embryo formed from the zygote, the endosperm, triploid, the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization, which involves the fusion of two male gametes with the egg cell and the central cell to form the primary endosperm and the zygote. Right after fertilization, the zygote is inactive, but the primary endosperm divides to form the endosperm tissue.
This tissue becomes the food the young plant will consume until the roots have developed after germination. After fertilization the ovules develop into the seeds; the ovule consists of a number of components: The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, at the pericarp. The nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops; the micropyle, a small pore or opening in the apex of the integument of the ovule where the pollen tube enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, where integument and nucellus are joined together; the shape of the ovules as they develop affects the final shape of the seeds. Plants produce ovules of four shapes: the most common shape is called anatropous, with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have a curved megagametophyte giving the seed a tight "C" shape.
The last ovule shape is called amphitropous, where the ovule is inverted and turned back 90 degrees on its stalk. In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, this establishes the polarity of the embryo; the upper or chalazal pole becomes the main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufactures nutrients from the endosperm that are used during the embryo's growth; the main components of the embryo are: The cotyledons, the seed leaves, attached to the embryonic axis. There may be two; the cotyledons are the source of nutrients in the non-endospermic dicotyledons, in which case they replace the endosperm, are thick and leathery. In endospermic seeds the cotyledons are papery. Dicotyledons have the point of attachment opposite one another on the axis; the epicotyl, the embryonic axis above the point of attachment of the cotyledon.
The plumule, the tip of the epicotyl, has a feathery appearance due to the presence of young leaf primordia at the apex, will become the shoot upon germination. The hypocotyl, the embryonic axis below the point of attachment of the cotyledon, connecting the epicotyl and the radicle, being the stem-root transition zone; the radicle, the basal tip of the hy
Sorbus aucuparia called rowan and mountain-ash, is a species of deciduous tree or shrub in the rose family. It is a variable species, botanists have used different definitions of the species to include or exclude trees native to certain areas; the range extends from Iceland to Russia and northern China. Unlike many plants with similar distributions, it is not native to Japan. S. Aucuparia has a slender trunk with smooth bark, a loose and roundish crown, its leaves are pinnate in pairs of leaflets on a central vein with a terminal leaflet, it blossoms from May to June in dense corymbs of small yellowish white flowers and develops small red pomes as fruit that ripen from August to October and are eaten by many bird species. The plant is undemanding and frost hardy and colonizes disrupted and inaccessible places as a short-lived pioneer species. Fruit and foliage of S. aucuparia have been used by humans in the creation of dishes and beverages, as a folk medicine, as fodder for livestock. Its tough and flexible wood has traditionally been used for woodworking.
It is planted to fortify soil in mountain regions or as an ornamental tree and has several cultivars. The binomial name Sorbus aucuparia is composed of the Latin words sorbus for service tree and aucuparia, which derives from the words avis for "bird" and capere for "catching" and describes the use of the fruit of S. aucuparia as bait for fowling. The plant is known as rowan and mountain-ash, has been called Amur mountain-ash, European mountain-ash, quick beam, quickbeam, or rowan-berry; the names rowan and mountain ash may be applied to other species in Sorbus subgenus Sorbus, mountain ash may be used for several other distantly related trees. The species is unrelated to the true ash trees, which carry pinnate leaves or the species Eucalyptus regnans called mountain ash, native to Tasmania and Victoria in southeastern Australia. S. aucuparia was categorized as Pyrus aucuparia. The author citation Sorbus aucuparia L. belongs to Carl Linnaeus. Sorbus aucuparia occurs as a shrub that grows up to between 5 and 15 m in height.
The crown is loose and roundish or irregularly shaped but wide and the plant grows multiple trunks. A trunk is slender and cylindrical and reaches up to 40 cm in diameter, the branches stick out and are slanted upwards; the bark of a young S. aucuparia is yellowish gray and gleaming and becomes gray-black with lengthwise cracks in advanced age. Lenticels in the bark are colored a bright ocher; the plant does not grow older than 80 years and is one of the shortest-lived trees in temperate climate. Wood of S. aucuparia has a light brown to reddish brown heartwood. It is diffuse-porous, flexible and tough, but not durable, with a density of 600 to 700 kg/m3 in a dried state; the roots of S. aucuparia grow wide and deep, the plant is capable of root sprouting and can regenerate after coppicing. The compound leaves are pinnate with 4 to 9 pairs of leaflets on either side of a terete central vein and with a terminal leaflet. There are paired leaf-like stipules at the base of the petiole; the leaves are up to 20 cm long, 8 to 12 cm wide, arranged in an alternate leaf pattern on a branch.
Distinguishing them from those of ash, Fraxinus excelsior, which are opposite and without stipules. The leaflets are elongated-lanceolate in shape, 2 to 6 cm long, 1 to 2.5 cm wide with a serrated edge, have short stems or sit close to the central vein except for the outermost leaflet. Leaflets are covered in gray-silvery hairs after sprouting but become bare after they unfold, their upper side is dark green and their underside is a grayish green and felted. Young leaflets smell like marzipan; the leaflets are asymmetrical at the bottom. S. aucuparia foliage turns yellow in autumn or a dark red in dry locations. Buds of S. aucuparia are longer than 1 cm and have flossy to felted hairs. These hairs, which disappear over time, cover dark brown to black bud scales; the terminal buds are oval and pointed and larger than axillary buds, which are narrow and pointed, close to the twig, curved towards it. S. aucuparia is monoecious. It reaches maturity at age 10 and carries ample fruit every year; the plant flowers from May to June in many yellowish white corymbs.
The corymbs are large and bulging. The flowers are between 8 and 10 mm in diameter and have five small, yellowish green, triangular sepals that are covered in hairs or bare; the five round or oval petals are yellowish white and the flower has up to 25 stamens fused with the corolla to form a hypanthium and an ovary with two to five styles. Flowers of S. aucuparia have an unpleasant trimethylamine smell. Their nectar is high in glucose, its fruit are round pomes between 10 mm in diameter that ripen from August to October. The fruit are green before they ripen and typically turn to orange or scarlet in color; the sepals persist as a five-pointed star on the ripe fruit. A corymb carries 80 to 100 pomes. A pome contains a star-shaped ovary with two to five locules each containing one or two flat and pointed reddish seeds; the flesh of the fruit contains carotenoids, citric acid, malic acid, parasorbic acid, provitamin A, sorbitol and vitamin C. The seeds contain glycoside. Sorbus aucuparia has a chromosome number of 2n=34.
Sorbus aucuparia is found in five subspecies: Sorbus aucuparia subsp. Aucuparia: found in most of the
Asia is Earth's largest and most populous continent, located in the Eastern and Northern Hemispheres. It shares the continental landmass of Eurasia with the continent of Europe and the continental landmass of Afro-Eurasia with both Europe and Africa. Asia covers an area of 44,579,000 square kilometres, about 30% of Earth's total land area and 8.7% of the Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Asia is notable for not only its overall large size and population, but dense and large settlements, as well as vast populated regions, its 4.5 billion people constitute 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, on the north by the Arctic Ocean; the border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It has moved since its first conception in classical antiquity.
The division of Eurasia into two continents reflects East–West cultural and ethnic differences, some of which vary on a spectrum rather than with a sharp dividing line. The most accepted boundaries place Asia to the east of the Suez Canal separating it from Africa. China and India alternated in being the largest economies in the world from 1 to 1800 CE. China was a major economic power and attracted many to the east, for many the legendary wealth and prosperity of the ancient culture of India personified Asia, attracting European commerce and colonialism; the accidental discovery of a trans-Atlantic route from Europe to America by Columbus while in search for a route to India demonstrates this deep fascination. The Silk Road became the main east–west trading route in the Asian hinterlands while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism as well as robust population growth during the 20th century, but overall population growth has since fallen. Asia was the birthplace of most of the world's mainstream religions including Hinduism, Judaism, Buddhism, Taoism, Islam, Sikhism, as well as many other religions.
Given its size and diversity, the concept of Asia—a name dating back to classical antiquity—may have more to do with human geography than physical geography. Asia varies across and within its regions with regard to ethnic groups, environments, historical ties and government systems, it has a mix of many different climates ranging from the equatorial south via the hot desert in the Middle East, temperate areas in the east and the continental centre to vast subarctic and polar areas in Siberia. The boundary between Asia and Africa is the Red Sea, the Gulf of Suez, the Suez Canal; this makes Egypt a transcontinental country, with the Sinai peninsula in Asia and the remainder of the country in Africa. The border between Asia and Europe was defined by European academics; the Don River became unsatisfactory to northern Europeans when Peter the Great, king of the Tsardom of Russia, defeating rival claims of Sweden and the Ottoman Empire to the eastern lands, armed resistance by the tribes of Siberia, synthesized a new Russian Empire extending to the Ural Mountains and beyond, founded in 1721.
The major geographical theorist of the empire was a former Swedish prisoner-of-war, taken at the Battle of Poltava in 1709 and assigned to Tobolsk, where he associated with Peter's Siberian official, Vasily Tatishchev, was allowed freedom to conduct geographical and anthropological studies in preparation for a future book. In Sweden, five years after Peter's death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Urals as the border of Asia. Tatishchev announced; the latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century; the border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is placed along the crest of the Caucasus Mountains, although it is sometimes placed further north; the border between Asia and the region of Oceania is placed somewhere in the Malay Archipelago.
The Maluku Islands in Indonesia are considered to lie on the border of southeast Asia, with New Guinea, to the east of the islands, being wholly part of Oceania. The terms Southeast Asia and Oceania, devised in the 19th century, have had several vastly different geographic meanings since their inception; the chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the colonial possessions of the various empires there. Lewis and Wigen assert, "The narrowing of'Southeast Asia' to its present boundaries was thus a gradual process." Geographical Asia is a cultural artifact of European conceptions of the world, beginning with the Ancient Greeks, being imposed onto other cultures, an imprecise concept causing endemic contention about what it means. Asia does not correspond to the cultural borders of its various types of constituents. From the time of Herodotus a minority of geographers have rejected the three-continent system on the grounds that there is no substantial physical separation between
Connecticut is the southernmost state in the New England region of the United States. As of the 2010 Census, it has the highest per-capita income, Human Development Index, median household income in the United States, it is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, Long Island Sound to the south. Its capital is Hartford and its most populous city is Bridgeport, it is part of New England, although portions of it are grouped with New York and New Jersey as the Tri-state area. The state is named for the Connecticut River which bisects the state; the word "Connecticut" is derived from various anglicized spellings of an Algonquian word for "long tidal river". Connecticut's first European settlers were Dutchmen who established a small, short-lived settlement called Fort Hoop in Hartford at the confluence of the Park and Connecticut Rivers. Half of Connecticut was part of the Dutch colony New Netherland, which included much of the land between the Connecticut and Delaware Rivers, although the first major settlements were established in the 1630s by the English.
Thomas Hooker led a band of followers from the Massachusetts Bay Colony and founded the Connecticut Colony. The Connecticut and New Haven colonies established documents of Fundamental Orders, considered the first constitutions in America. In 1662, the three colonies were merged under a royal charter; this was one of the Thirteen Colonies. Connecticut is the third smallest state by area, the 29th most populous, the fourth most densely populated of the 50 states, it is known as the "Constitution State", the "Nutmeg State", the "Provisions State", the "Land of Steady Habits". It was influential in the development of the federal government of the United States; the Connecticut River, Thames River, ports along Long Island Sound have given Connecticut a strong maritime tradition which continues today. The state has a long history of hosting the financial services industry, including insurance companies in Hartford and hedge funds in Fairfield County. Landmarks and cities of Connecticut Connecticut is bordered on the south by Long Island Sound, on the west by New York, on the north by Massachusetts, on the east by Rhode Island.
The state capital and fourth largest city is Hartford, other major cities and towns include Bridgeport, New Haven, Waterbury, Danbury, New Britain and Bristol. Connecticut is larger than the country of Montenegro. There are 169 incorporated towns in Connecticut; the highest peak in Connecticut is Bear Mountain in Salisbury in the northwest corner of the state. The highest point is just east of where Connecticut and New York meet, on the southern slope of Mount Frissell, whose peak lies nearby in Massachusetts. At the opposite extreme, many of the coastal towns have areas that are less than 20 feet above sea level. Connecticut has a long maritime history and a reputation based on that history—yet the state has no direct oceanfront; the coast of Connecticut sits on Long Island Sound, an estuary. The state's access to the open Atlantic Ocean is both to the east; this situation provides many safe harbors from ocean storms, many transatlantic ships seek anchor inside Long Island Sound when tropical cyclones pass off the upper East Coast.
The Connecticut River cuts through the center of the state. The most populous metropolitan region centered within the state lies in the Connecticut River Valley. Despite Connecticut's small size, it features wide regional variations in its landscape. Connecticut's rural areas and small towns in the northeast and northwest corners of the state contrast with its industrial cities such as Stamford and New Haven, located along the coastal highways from the New York border to New London northward up the Connecticut River to Hartford. Many towns in northeastern and northwestern Connecticut center around a green, such as the Litchfield Green, Lebanon Green, Wethersfield Green. Near the green stand historical visual symbols of New England towns, such as a white church, a colonial meeting house, a colonial tavern or inn, several colonial houses, so on, establishing a scenic historical appearance maintained for both historic preservation and tourism. Many of the areas in southern and coastal Connecticut have been built up and rebuilt over the years, look less visually like traditional New England.
The northern boundary of the state with Massachusetts is marked by the Southwick Jog or Granby Notch, an 2.5 miles square detour into Connecticut. The origin of this anomaly is established in a long line of disputes and temporary agreements which were concluded in 1804, when southern Southwick's residents sought to leave Massachusetts, the town was split in half; the southwestern border of Connecticut where it abuts New York State is marked by a panhandle in Fairfield County, containing the towns of Greenwich, New Canaan and parts of Norwalk and Wilton. This irregularity in the boundary is the result of territorial disputes in the late 17th century, culminating
Fraxinus, English name ash, is a genus of flowering plants in the olive and lilac family, Oleaceae. It contains 45–65 species of medium to large trees deciduous, though a few subtropical species are evergreen; the genus is widespread across much of Europe and North America. The tree's common English name, "ash", traces back to the Old English æsc which relates to the Proto-Indo-European for the tree, while the generic name originated in Latin from a Proto-Indo-European word for birch. Both words are used to mean "spear" in their respective languages as the wood is good for shafts; the leaves are opposite, pinnately compound, simple in a few species. The seeds, popularly known as "keys" or "helicopter seeds", are a type of fruit known as a samara. Most Fraxinus species are dioecious, having male and female flowers on separate plants but gender in ash is expressed as a continuum between male and female individuals, dominated by unisexual trees. With age, ash may change their sexual function from predominantly male and hermaphrodite towards femaleness.
Rowans or mountain ashes have leaves and buds superficially similar to those of true ashes, but belong to the unrelated genus Sorbus in the rose family. Species arranged into sections supported by phylogenetic analysis. Section DipetalaeFraxinus anomala Torr. Ex S. Watson – singleleaf ash Fraxinus dipetala Hook. & Arn. – California ash or two-petal ash Fraxinus quadrangulata Michx. – blue ash Fraxinus trifoliataSection FraxinusFraxinus angustifolia Vahl – narrow-leafed ash Fraxinus angustifolia subsp. Oxycarpa – Caucasian ash Fraxinus angustifolia subsp. Syriaca Fraxinus excelsior L. – European ash Fraxinus holotricha Koehne Fraxinus mandschurica Rupr. – Manchurian ash Fraxinus nigra Marshall – black ash Fraxinus pallisiae Wilmott – Pallis' ash Fraxinus sogdiana BgeSection Melioides sensu latoFraxinus chiisanensis Fraxinus cuspidata Torr. – fragrant ash Fraxinus platypoda Fraxinus spaethiana Lingelsh. – Späth's ashSection Melioides sensu strictoFraxinus albicans Buckley – Texas ash Fraxinus americana L. – white ash or American ash Fraxinus berlandieriana DC.
– Mexican ash Fraxinus caroliniana Mill. – Carolina ash Fraxinus latifolia Benth. – Oregon ash Fraxinus papillosa Lingelsh. – Chihuahua ash Fraxinus pennsylvanica Marshall – green ash Fraxinus profunda Bush – pumpkin ash Fraxinus uhdei Lingelsh. – Shamel ash or tropical ash Fraxinus velutina Torr. – velvet ash or Arizona ashSection OrnusFraxinus apertisquamifera Fraxinus baroniana Fraxinus bungeana DC. – Bunge's ash Fraxinus chinensis Roxb. – Chinese ash or Korean ash Fraxinus floribunda Wall. – Himalayan manna ash Fraxinus griffithii C. B. Clarke – Griffith's ash Fraxinus japonica – Japanese ash Fraxinus lanuginosa – Japanese ash Fraxinus longicuspis Fraxinus malacophylla Fraxinus micrantha Lingelsh. Fraxinus ornus L. – manna ash or flowering ash Fraxinus paxiana Lingelsh. Fraxinus sieboldiana Blume – Japanese flowering ashSection PaucifloraeFraxinus dubia Fraxinus gooddingii – Goodding's ash Fraxinus greggii A. Gray – Gregg's ash Fraxinus purpusii Fraxinus rufescensSection SciadanthusFraxinus dimorpha Fraxinus hubeiensis Ch'u & Shang & Su – 湖北梣 hu bei qin Fraxinus xanthoxyloides Wall.
Ex DC. – Afghan ash North American native ash tree species are a critical food source for North American frogs, as their fallen leaves are suitable for tadpoles to feed upon in ponds, large puddles, other water bodies. Lack of tannins in the American ash makes their leaves a good food source for the frogs, but reduces its resistance to the ash borer. Species with higher leaf tannin levels are taking the place of native ash, thanks to their greater resistance to the ash borer, they produce much less suitable food for the tadpoles, resulting in poor survival rates and small frog sizes. Ash species native to North America provide important habit and food for various other creatures native to North America, such as a long-horn beetle, avian species, mammalian species. Ash is used as a food plant by the larvae of some Lepidoptera species; the emerald ash borer is a wood-boring beetle accidentally introduced to North America from eastern Asia via solid wood packing material in the late 1980s to early 1990s.
It has killed tens of millions of trees in 22 states in the United States and adjacent Ontario and Quebec in Canada. It threatens some seven billion ash trees in North America. Research is being conducted to determine if three native Asian wasps that are natural predators of EAB could be used as a biological control for the management of EAB populations in the United States; the public is being cautioned not to transport unfinished wood products, such as firewood, to slow the spread of this insect pest. The European ash, Fraxinus excelsior, has been affected by the fungus Hymenoscyphus fraxineus, causing ash dieback in a large number of trees since the mid-1990s in eastern and northern Europe; the disease has infected about 90% of Denmark's ash trees. At the end of October 2012 in the UK, the Food and Environment Research Agency reported that ash dieback had been discovered in mature woodland in Suffolk. In 2016, the ash tree was reported as in danger of extinction in Europe. Ash is a hardwood and is hard, dense and strong but elastic, extensively used for making bows, tool handles, baseball bats and other uses demanding high strength and resilience.
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines, shrubs. Bark is a nontechnical term, it consists of the inner bark and the outer bark. The inner bark, which in older stems is living tissue, includes the innermost area of the periderm; the outer bark in older stems includes the dead tissue on the surface of the stems, along with parts of the innermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the last formed periderm is called the rhytidome. Products derived from bark include: bark shingle siding and wall coverings and other flavorings, tanbark for tannin, latex, poisons, various hallucinogenic chemicals and cork. Bark has been used to make cloth and ropes and used as a surface for paintings and map making. A number of plants are grown for their attractive or interesting bark colorations and surface textures or their bark is used as landscape mulch. What is called bark includes a number of different tissues.
Cork is an external, secondary tissue, impermeable to water and gases, is called the phellem. The cork is produced by the cork cambium, a layer of meristematically active cells which serve as a lateral meristem for the periderm; the cork cambium, called the phellogen, is only one cell layer thick and it divides periclinally to the outside producing cork. The phelloderm, not always present in all barks, is a layer of cells formed by and interior to the cork cambium. Together, the phellem and phelloderm constitute the periderm. Cork cell walls contain suberin, a waxy substance which protects the stem against water loss, the invasion of insects into the stem, prevents infections by bacteria and fungal spores; the cambium tissues, i.e. the cork cambium and the vascular cambium, are the only parts of a woody stem where cell division occurs. Phloem is a nutrient-conducting tissue composed of sieve tubes or sieve cells mixed with parenchyma and fibers; the cortex is the primary tissue of roots. In stems the cortex is between the epidermis layer and the phloem, in roots the inner layer is not phloem but the pericycle.
From the outside to the inside of a mature woody stem, the layers include: Bark Periderm Cork, includes the rhytidome Cork cambium Phelloderm Cortex Phloem Vascular cambium Wood Sapwood Heartwood Pith In young stems, which lack what is called bark, the tissues are, from the outside to the inside: Epidermis, which may be replaced by periderm Cortex Primary and secondary phloem Vascular cambium Secondary and primary xylem. As the stem ages and grows, changes occur that transform the surface of the stem into the bark; the epidermis is a layer of cells that cover the plant body, including the stems, leaves and fruits, that protects the plant from the outside world. In old stems the epidermal layer and primary phloem become separated from the inner tissues by thicker formations of cork. Due to the thickening cork layer these cells die; this dead layer is the rough corky bark that forms around other stems. A secondary covering called the periderm forms on small woody stems and many non-woody plants, composed of cork, the cork cambium, the phelloderm.
The periderm forms from the phellogen. The periderm replaces the epidermis, acts as a protective covering like the epidermis. Mature phellem cells have suberin in their walls to protect the stem from desiccation and pathogen attack. Older phellem cells are dead; the skin on the potato tuber constitutes the cork of the periderm. In woody plants the epidermis of newly grown stems is replaced by the periderm in the year; as the stems grow a layer of cells form under the epidermis, called the cork cambium, these cells produce cork cells that turn into cork. A limited number of cell layers may form interior to the cork cambium, called the phelloderm; as the stem grows, the cork cambium produces new layers of cork which are impermeable to gases and water and the cells outside the periderm, namely the epidermis and older secondary phloem die. Within the periderm are lenticels, which form during the production of the first periderm layer. Since there are living cells within the cambium layers that need to exchange gases during metabolism, these lenticels, because they have numerous intercellular spaces, allow gaseous exchange with the outside atmosphere.
As the bark develops, new lenticels are formed within the cracks of the cork layers. The rhytidome is the most familiar part of bark, being the outer layer that covers the trunks of trees, it is composed of dead cells and is produced by the formation of multiple layers of suberized periderm and phloem tissue. The rhytidome is well developed in older stems and roots of trees. In shrubs, older bark is exfoliated and thick rhytidome accumulates, it is thickest and most distinctive at the trunk or bole of the tree. Bark tissues make up by weight between 10–20% of woody vascular plants and consists of various biopolymers, lignin, suberin and polysaccharides. Up to 40% of the bark tissue is made of lignin which forms an important part of a plant providing stru
Nova Scotia is one of Canada's three Maritime Provinces, one of the four provinces that form Atlantic Canada. Its provincial capital is Halifax. Nova Scotia is the second-smallest of Canada's ten provinces, with an area of 55,284 square kilometres, including Cape Breton and another 3,800 coastal islands; as of 2016, the population was 923,598. Nova Scotia is Canada's second-most-densely populated province, after Prince Edward Island, with 17.4 inhabitants per square kilometre. "Nova Scotia" means "New Scotland" in Latin and is the recognized English-language name for the province. In both French and Scottish Gaelic, the province is directly translated as "New Scotland". In general and Slavic languages use a direct translation of "New Scotland", while most other languages use direct transliterations of the Latin / English name; the province was first named in the 1621 Royal Charter granting to Sir William Alexander in 1632 the right to settle lands including modern Nova Scotia, Cape Breton Island, Prince Edward Island, New Brunswick and the Gaspé Peninsula.
Nova Scotia is Canada's smallest province in area after Prince Edward Island. The province's mainland is the Nova Scotia peninsula surrounded by the Atlantic Ocean, including numerous bays and estuaries. Nowhere in Nova Scotia is more than 67 km from the ocean. Cape Breton Island, a large island to the northeast of the Nova Scotia mainland, is part of the province, as is Sable Island, a small island notorious for its shipwrecks 175 km from the province's southern coast. Nova Scotia has many ancient fossil-bearing rock formations; these formations are rich on the Bay of Fundy's shores. Blue Beach near Hantsport, Joggins Fossil Cliffs, on the Bay of Fundy's shores, has yielded an abundance of Carboniferous-age fossils. Wasson's Bluff, near the town of Parrsboro, has yielded both Triassic- and Jurassic-age fossils; the province contains 5,400 lakes. Nova Scotia lies in the mid-temperate zone and, although the province is surrounded by water, the climate is closer to continental climate rather than maritime.
The winter and summer temperature extremes of the continental climate are moderated by the ocean. However, winters are cold enough to be classified as continental—still being nearer the freezing point than inland areas to the west; the Nova Scotian climate is in many ways similar to the central Baltic Sea coast in Northern Europe, only wetter and snowier. This is true in spite of Nova Scotia's being some fifteen parallels south. Areas not on the Atlantic coast experience warmer summers more typical of inland areas, winter lows a little colder. Described on the provincial vehicle licence plate as Canada's Ocean Playground, Nova Scotia is surrounded by four major bodies of water: the Gulf of Saint Lawrence to the north, the Bay of Fundy to the west, the Gulf of Maine to the southwest, Atlantic Ocean to the east; the province includes regions of the Mi'kmaq nation of Mi'kma'ki. The Mi'kmaq people inhabited Nova Scotia at the time the first European colonists arrived. In 1605, French colonists established the first permanent European settlement in the future Canada at Port Royal, founding what would become known as Acadia.
The British conquest of Acadia took place in 1710. The Treaty of Utrecht in 1713 formally recognized this and returned Cape Breton Island to the French. Present-day New Brunswick still formed a part of the French colony of Acadia. After the capture of Port Royal in 1710, Francis Nicholson announced it would be renamed Annapolis Royal in honor of Queen Anne. In 1749, the capital of Nova Scotia moved from Annapolis Royal to the newly established Halifax. In 1755 the vast majority of the French population was forcibly removed in the Expulsion of the Acadians. In 1763, most of Acadia became part of Nova Scotia. In 1769, St. John's Island became a separate colony. Nova Scotia included present-day New Brunswick until that province's establishment in 1784, after the arrival of United Empire Loyalists. In 1867, Nova Scotia became one of the four founding provinces of the Canadian Confederation; the warfare on Nova Scotian soil during the 17th and 18th centuries influenced the history of Nova Scotia. The Mi'kmaq had lived in Nova Scotia for centuries.
The French arrived in 1604, Catholic Mi'kmaq and Acadians formed the majority of the population of the colony for the next 150 years. During the first 80 years the French and Acadians lived in Nova Scotia, nine significant military clashes took place as the English and Scottish and French fought for possession of the area; these encounters happened at Port Royal, Saint John, Cap de Sable and Baleine. The Acadian Civil War took place from 1640 to 1645. Beginning with King William's War in 1688, six wars took place in Nova Scotia before the British defeated the French and made peace with the Mi'kmaq: King William's War, Queen Anne's War, Father Rale's War, King George's War, Father Le Loutre’s War The Seven Years' War called the French and Indian War The battles during these wars took place Port Royal, Saint John, Chignecto, Dartmouth and Grand-Pré. Despite the British conquest of Acadia in 1710, Nova Scotia remained occupied