Allium stellatum |
Allium cepa |
|
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autumn onion, prairie onion |
cultivated onion, garden onion |
|
Bulbs | 1–5+, usually clustered, often short-rhizomatous at base, rhizome not stout or iris-like, ovoid, 2–4 × 1–2.5 cm; outer coats enclosing 1 or more bulbs, grayish or brownish, membranous, fibers parallel, few, or sometimes reticulate, cells obscure, finely meshed; inner coats whitish to pinkish, cells obscure, ± quadrate. |
1–3, not rhizomatous, mostly depressed-globose, varying in size from cultivar to cultivar, 5–8 × 3–10 cm; outer coats enclosing 1 or more bulbs, yellowish brown, red, or white, membranous, without reticulation; inner coats white to pink, cells obscure to quadrate. |
Leaves | persistent, green at anthesis, 3–5, basally sheathing, sheaths never extending much above soil level; blade solid, flat, channeled, 14–35 cm × 1–5 mm, margins ± entire. |
persistent, 4–10, sheathing proximal 1/6–1/4 scape; blade fistulose, usually ± semicircular in cross section, 10–50 cm × 4–20 mm. |
Scape | persistent, solitary, erect, or, if nodding at anthesis, becoming erect, solid, terete or ± 4-angled, particularly distally, 20–50 cm × 1–3.5 mm. |
persistent, solitary, erect, fistulose, inflated below middle, 30–100 cm × 3–20 mm. |
Umbel | persistent, nodding, becoming erect, ± loose, 9–40-flowered, hemispheric, bulbils unknown; spathe bracts persistent, 2, 2–4-veined, lanceolate, ± equal, apex acuminate. |
persistent, erect, compact, to 500-flowered, globose, bulbils occasionally found; spathe bracts caducous, 2–3, 3–4-veined, ovate, ± equal, apex acute to acuminate. |
Flowers | stellate, 5–8 mm; tepals spreading, deep pink, elliptic-lanceolate, ± equal, withering in fruit, margins entire, apex acute, midribs not thickened; stamens exserted; anthers yellow; pollen yellow; ovary conspicuously crested; processes 6, distinct, flattened, ± triangular, margins entire or toothed; style exserted, linear, ± equaling stamens; stigma capitate, scarcely thickened, unlobed; pedicel 0–20 mm. |
stellate to campanulate to urceolate, 3–7 mm; tepals erect to ± spreading, white to pink with greenish midveins, withering in fruit, margins entire, apex obtuse or acute, outer ovate, inner oblong; stamens exserted; anthers white; pollen white; ovary crestless; style linear, ± equaling stamens; stigma capitate, unlobed; pedicel 10–50 mm. |
Seed | coat dull; cells minutely roughened. |
coat not known. |
2n | = 14. |
|
Allium stellatum |
Allium cepa |
|
Phenology | Flowering Jul–Oct. | Flowering Jun–Aug. |
Habitat | Often on calcareous soils | Disturbed sites adjacent to areas where cultivated |
Elevation | 300–2200 m (1000–7200 ft) | 0–500 m (0–1600 ft) |
Distribution |
AR; IA; IL; KS; MI; MN; MO; ND; NE; OK; SD; TN; TX; WI; MB; ON; SK
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AR; CA; KS; LA; MT; OR; TX; WA; cultivated in Europe; Asia
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Discussion | The onion of commerce, Allium cepa is widely cultivated as a biennial in North America, Europe, and Asia. It is unknown in the wild and is probably derived from A. oschanini of central Asia. The cultivated form is often polyploid (2n = 16, 32, 54) and possibly of hybrid origin. It exists in numerous cultivars, a few of which form large bulbils in the umbel. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 26. | FNA vol. 26, p. 244. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Ker Gawler: Bot. Mag. 38: plate 1576. (1813) | Linnaeus: Sp. Pl. 1: 301. (1753) |
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