98. Allium cepa Linnaeus, Sp. Pl. 1: 300. 1753.
洋葱 yang cong
Bulb solitary or clustered, applanate-globose to cylindric-ovoid; tunic purple-red, brown-red, pale brown-red, or yellow to pale yellow, papery to thinly leathery, entire. Leaves shorter than scape, 0.5--2 cm wide, terete, fistulose. Scape developed or not, if developed then to 1 m, terete, conspicuously inflated below middle, fistulose, covered with leaf sheaths only at base. Spathe 2- or 3-valved, persistent. Umbel globose, densely many flowered or with bulblets and a few flowers. Pedicels equal, ca. 5 × as long as perianth, bracteolate. Perianth chalk white or white; segments with green or pale red midvein, oblong-ovate, 4--5 × ca. 2 mm. Filaments equal, slightly longer than perianth segments, connate at base for ca. 1/5 their length, adnate to perianth segments for 1/2 of connate part; outer ones subulate; inner ones broadened at base, 1-toothed on each side. Ovary subglobose, with concave nectaries covered by hoodlike projections at base. Style slightly exserted. Fl. and fr. May--Jul. 2 n = 16*, 32.
Cultivated as a vegetable. Throughout China [widely cultivated elsewhere].