About Allium praescissum Rchb.
Allium praescissum Rchb. belongs to the genus Allium, commonly called alliums. All alliums are herbaceous geophyte perennials that grow from true bulbs. Some of these bulbs grow on rhizomes, and all alliums carry a distinct onion or garlic odor and flavor. The bulbs of Allium species are either solitary or clustered, and are tunicate. Perennial growth occurs when new bulbs form annually from the base of old bulbs, at the ends of rhizomes, or in a small number of species at the ends of stolons. A small number of Allium species also have tuberous roots. The outer coats of Allium bulbs are typically brown or grey, with a texture that can be smooth, fibrous, or marked by cellular reticulation, while the inner coats of the bulbs are membranous. Most Allium species produce basal leaves, which often wither from the tip down before or during flowering, though some species keep persistent foliage. Each plant produces between one and 12 leaves; most species have linear, channeled or flat leaf blades. Leaf blades are either straight or variously coiled, but some species such as A. victorialis and A. tricoccum have broad leaves. Allium leaves are sessile, and only very rarely narrow to form a petiole. Flowers grow on scapes, and are either erect or, in some species, pendent. They have six petal-like tepals arranged in two whorls, one style, and six epipetalous stamens. Anther and pollen color varies by species. Ovaries are superior, three-lobed, and contain three locules. Fruits take the form of capsules that open longitudinally along the capsule wall between the partitions of the locule. Seeds are black and rounded. Flowering scapes are either terete or flattened, and are normally persistent. Allium inflorescences are umbels, where the outermost flowers bloom first, and flowering progresses inward toward the center of the umbel. Some species produce bulbils within their umbels, and in some species such as Allium paradoxum, bulbils replace some or all of the flowers. Umbels are subtended by noticeable spathe bracts, which are commonly fused and usually have around three veins. Some bulbous alliums reproduce both by seed and by forming small new bulbs, called offsets, around the original older bulb. Several species can produce many bulbils in their flower heads; the so-called tree onion or Egyptian onion (A. × proliferum) produces only a few bulbils, but these are large enough to be pickled. Many Allium species have been used as food across their native ranges. Several unrelated poisonous species resemble Alliums in appearance, for example death camas (Toxicoscordion venenosum) in North America, but none of these lookalikes have the characteristic scent of onion or garlic. The majority of Allium species are native to the Northern Hemisphere, distributed across the holarctic region from dry subtropics to the boreal zone, with the highest concentration of species in Asia. 138 Allium species occur in China, which accounts for about one sixth of all recognized Allium species and represents five subgenera of the genus. Only a few species are native to Africa and Central and South America. Allium dregeanum is the single known exception to the Northern Hemisphere native range, growing in South Africa in the Southern Hemisphere. The genus has two centres of diversity: a major centre stretching from the Mediterranean Basin to Central Asia and Pakistan, and a minor centre in western North America. The genus is particularly diverse in the eastern Mediterranean. Allium species grow in a wide range of conditions, from dry, well-drained mineral soils to moist, organic soils. Most species grow in sunny locations, but a number also grow in forests, such as A. ursinum, or even in swamps or water. The larvae of the leek moth and onion feed on various Allium species, along with the larvae of many other Lepidoptera, including cabbage moth, common swift moth (recorded feeding on garlic), garden dart moth, large yellow underwing moth, nutmeg moth, setaceous Hebrew character moth, turnip moth, and Schinia rosea, a moth that feeds exclusively on Allium species. Dogs and cats are very susceptible to poisoning after consuming certain Allium species. Cattle have also occasionally developed onion toxicosis. Allium vegetables can cause digestive disorders in humans. Many Allium species have been harvested by humans throughout history, but only around a dozen remain economically important today as agricultural crops or garden vegetables. The genus includes many economically important species: these include onions (A. cepa), French shallots (A. oschaninii), leeks (A. ampeloprasum), garlic (A. sativum), and culinary herbs such as scallions (multiple Allium species) and chives (A. schoenoprasum). Some Allium species have also been used in traditional medicine. This genus also includes species that are still commonly gathered from the wild, such as wild garlic (Allium ursinum) in Europe and ramps (Allium tricoccum) in North America.
