Helianthus
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Helianthus
''Helianthus'' () is a genus comprising around 70 species of annual and perennial flowering plants in the daisy family Asteraceae commonly known as sunflowers. Except for three South American species, the species of ''Helianthus'' are native to North America and Central America. The best-known species is the common sunflower (''Helianthus annuus''). This and other species, notably Jerusalem artichoke (''H. tuberosus''), are cultivated in temperateness, temperate regions and some tropical regions, as food crops for humans, cattle, and poultry, and as ornamental plants. The species ''H. annuus'' typically grows during the summer and into early fall, with the peak growth season being mid-summer. Several perennial ''Helianthus'' species are grown in gardens, but have a tendency to spread rapidly and can become aggressive. On the other hand, the whorled sunflower, ''Helianthus verticillatus'', was listed as an endangered species in 2014 when the U.S. Fish and Wildlife Service issued ...
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Sunflower Disk
The common sunflower (''Helianthus annuus'') is a species of large Annual plant, annual forb of the daisy family Asteraceae. The common sunflower is harvested for its Sunflower seed, edible oily seeds, which are often eaten as a snack food. They are also used in the production of cooking oil, as food for livestock, as bird food, and as plantings in domestic gardens for aesthetics. Wild plants are known for their multiple flower heads, whereas the domestic sunflower often possesses a single large flower head atop an unbranched stem. Description The plant has an erect rough-hairy stem, reaching typical heights of . The tallest sunflower on record achieved . Sunflower leaves are broad, coarsely toothed, rough and mostly alternate; those near the bottom are largest and commonly heart-shaped. Flower The plant flowers in summer. What is often called the "flower" of the sunflower is actually a "flower head" (pseudanthium), wide, of numerous small individual five-petaled flowers ...
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Helianthus Annuus
The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the production of cooking oil, as food for livestock, as bird food, and as plantings in domestic gardens for aesthetics. Wild plants are known for their multiple flower heads, whereas the domestic sunflower often possesses a single large flower head atop an unbranched stem. Description The plant has an erect rough-hairy stem, reaching typical heights of . The tallest sunflower on record achieved . Sunflower leaves are broad, coarsely toothed, rough and mostly alternate; those near the bottom are largest and commonly heart-shaped. Flower The plant flowers in summer. What is often called the "flower" of the sunflower is actually a "flower head" (pseudanthium), wide, of numerous small individual five-petaled flowers ("florets"). The outer f ...
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Jerusalem Artichoke
The Jerusalem artichoke (''Helianthus tuberosus''), also called sunroot, sunchoke, wild sunflower, topinambur, or earth apple, is a species of Helianthus, sunflower native to central North America. It is cultivated widely across the temperate zone for its tuber, which is used as a root vegetable.Purdue University Center for New Crops & Plants Products''Helianthus tuberosus''/ref> Description ''Helianthus tuberosus'' is a herbaceous perennial plant growing to tall with opposite leaf, leaves on the lower part of the stem but alternate towards the top. The leaves have a rough, hairy texture. Larger leaves on the lower stem are Leaf shape, broad ovoid-acute and can be up to long. Leaves higher on the stem are smaller and narrower. The flowers are yellow and produced in capitate inflorescence, flowerheads, which are in diameter, with 10–20 ray florets and 60 or more small disc florets. The flowers are briefly fragrant, giving off a light, vanilla-chocolate perfume. The tubers ...
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Asteraceae
Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of Extant taxon, extant species in each family is unknown. The Asteraceae were first described in the year 1740 and given the original name Composita, Compositae. The family is commonly known as the aster, Daisy (flower), daisy, composite, or sunflower family. Most species of Asteraceae are herbaceous plants, and may be Annual plant, annual, Biennial plant, biennial, or Perennial plant, perennial, but there are also shrubs, vines, and trees. The family has a widespread distribution, from subpolar to tropical regions, in a wide variety of habitats. Most occur in Hot desert climate, hot desert and cold or hot Semi-arid climate, semi-desert climates, and they are found on ever ...
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Pseudanthium
A pseudanthium (; : pseudanthia) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers, or capitula, which are special types of inflorescences in which anything from a small cluster to hundreds or sometimes thousands of flowers are grouped together to form a single flower-like structure. Pseudanthia take various forms. The real flowers (the florets) are generally small and often greatly reduced, but the pseudanthium itself can sometimes be quite large (as in the heads of some varieties of sunflower). Pseudanthia are characteristic of the daisy and sunflower family (biology), family (Asteraceae), whose flowers are differentiated into ray flowers and disk flowers, unique to this family. The disk flowers in the center of the pseudanthium are actinomorphic and the corolla (flower), corolla is fused into a tube. Flowers on th ...
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Florets
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names. A B ...
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Endangered Species Act
The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation", the ESA was signed into law by President Presidency of Richard Nixon#Environmental policy, Richard Nixon on December 28, 1973. The Supreme Court of the United States described it as "the most comprehensive legislation for the preservation of endangered species enacted by any nation"."Tennessee Valley Authority v. Hill"
437 U.S. 153 (1978) Retrieved 24 November 2015.
The purposes of the ESA are two-fold: to prevent extinction and to recover species to the point wher ...
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A Sunflower Seed Growing
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, '' a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest known ancestor of A is ''aleph''—the first letter of the Phoenician ...
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Annual Plant
An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. Globally, 6% of all plant species and 15% of herbaceous plants (excluding trees and shrubs) are annuals. The annual life cycle has independently emerged in over 120 different plant families throughout the entire angiosperm phylogeny. The evolutionary and ecological drivers of the annual life cycle Traditionally, there has been a prevailing assumption that annuals have evolved from perennial ancestors. However, recent research challenges this notion, revealing instances where perennials have evolved from annual ancestors. Intriguingly, models propose that transition rates from an annual to a perennial life cycle are twice as fast as the reverse transition. The life-history theory posits that annual plants are favored when adult mortality is higher than seedling (or seed) mortality, i.e., annuals will dominate environments with dis ...
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Cultivars
A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from deliberate human manipulation, but some originate from wild plants that have distinctive characteristics. Cultivar names are chosen according to rules of the International Code of Nomenclature for Cultivated Plants (ICNCP), and not all cultivated plants qualify as cultivars. Horticulturists generally believe the word ''cultivar''''Cultivar'' () has two meanings, as explained in '' Formal definition'': it is a classification category and a taxonomic unit within the category. When referring to a taxon, the word does not apply to an individual plant but to all plants that share the unique characteristics that define the cultivar. was coined as a term meaning "cultivated ...
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Petiole (botany)
In botany, the petiole () is the stalk that attaches the leaf blade to the Plant stem, stem. It is able to twist the leaf to face the sun, producing a characteristic foliage arrangement (spacing of blades), and also optimizing its exposure to sunlight. Outgrowths appearing on each side of the petiole in some species are called stipules. The terms wikt:petiolate, petiolate and wikt:apetiolate, apetiolate are applied respectively to leaves with and without petioles. Description The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves the leaf stalk may be long (as in the leaves of celery and rhubarb), or short (for example basil). When completely absent, the blade attaches directly to the stem and is said to be Sessility (botany), sessile or apetiolate. Subpetiolate leaves have an extremely short petiole, and may appear sessile. The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile. In some other plant group ...
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