Allium geyeri |
Allium cepa |
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Geyer's onion |
cultivated onion, garden onion |
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Bulbs | 2–10+, not rhizomatous, ovoid or more elongate, 1–2.5 × 0.8–2 cm; outer coats enclosing 1 or more bulbs, gray or brown, reticulate, cells rather coarse-meshed, open, fibrous; inner coats whitish, cells vertically elongate and regular or obscure. |
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. |
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Leaves | persistent, usually green at anthesis, usually 3–5, sheathing less than 1/4 scape; blade solid, ± straight, flat, channeled, (6–)12–30 cm × 1–3(–5) mm, margins entire or denticulate. |
persistent, 4–10, sheathing proximal 1/6–1/4 scape; blade fistulose, usually ± semicircular in cross section, 10–50 cm × 4–20 mm. |
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Scape | persistent, solitary, erect, terete or somewhat 2-angled, 10–50 cm × 1–3 mm. |
persistent, solitary, erect, fistulose, inflated below middle, 30–100 cm × 3–20 mm. |
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Umbel | persistent, erect, compact, 10–25-flowered, hemispheric to globose, not producing bulbils, or 0–5-flowered, largely replaced by ovoid, acuminate bulbils; spathe bracts persistent, 2–3, mostly 1-veined, ovate to lanceolate, ± equal, apex acuminate, beakless. |
persistent, erect, compact, to 500-flowered, globose, bulbils occasionally found; spathe bracts caducous, 2–3, 3–4-veined, ovate, ± equal, apex acute to acuminate. |
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Flowers | urceolate-campanulate, (4–)6–8(–10) mm; tepals erect or spreading, pink to white, ovate to lanceolate, ± equal, not withering in fruit and permanently investing fruit, or withering if fruit not produced, midribs papillose, becoming callous-keeled, margins often obscurely toothed, apex obtuse to acuminate; stamens included; anthers yellow; pollen yellow; ovary when present, inconspicuously crested; processes 6, central, low, distinct or connate in pairs across septa, ± erect, rounded, margins entire, becoming variously developed or obsolete in fruit; style linear, ± equaling stamens; stigma capitate, unlobed or obscurely lobed; pedicel becoming rigid and stiffly spreading in fruit, 8–13 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. |
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Seed | coat shining; cells each with minute, central papilla. |
coat not known. |
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Allium geyeri |
Allium cepa |
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Phenology | Flowering Jun–Aug. | |||||
Habitat | Disturbed sites adjacent to areas where cultivated | |||||
Elevation | 0–500 m (0–1600 ft) | |||||
Distribution |
w North America
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AR; CA; KS; LA; MT; OR; TX; WA; cultivated in Europe; Asia
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Discussion | Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 26, p. 237. | FNA vol. 26, p. 244. | ||||
Parent taxa | Liliaceae > Allium | Liliaceae > Allium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | S. Watson: Proc. Amer. Acad. Arts 14: 227. (1879) | Linnaeus: Sp. Pl. 1: 301. (1753) | ||||
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