Description from Flora of China
Herbs perennial, bulbiferous, sometimes with well-developed, thick or thin rhizomes, rarely with stolons or tuberous roots, usually with onionlike, leeklike, or garliclike odor when fresh. Bulb covered with a tunic. Leaves sessile, very rarely narrowed into a petiole, with a closed leaf sheath at base, linear, linear-lanceolate, or lorate to orbicular-ovate, cross section flat, angled, or semiterete to terete, fistulose or solid. Scape terminal or lateral, sheathed or naked. Inflorescence a terminal umbel, sometimes with bulblets, rarely flowerless and with bulblets only, enclosed in a spathelike bract before anthesis. Pedicels with or without basal bracteoles. Flowers bisexual, very rarely degenerating into unisexual (when plants dioecious). Perianth segments free or united into a tube at base. Filaments usually connate at base and adnate to perianth segments, entire or toothed. Ovary with 1 to several ovules per locule; septa often containing nectaries opening by pores at base of ovary. Style simple; stigma entire or 3-cleft. Capsule loculicidal. Seeds black, rhomboidal or spheroidal.
Most species of Allium are edible, and some have long been cultivated in China and elsewhere, e.g., A. cepa A. chinense A. fistulosum A. porrum A. sativum and A. tuberosum.
About 660 species: N hemisphere, mainly in Asia, some species in Africa and Central and South America; 138 species (50 endemic, five introduced) in China.
(Authors: Xu Jiemei (许介眉); Rudolf V. Kamelin)