familyLiliaceae
genusAllium

Allium cepa

Linnaeus

Sp. Pl. 1: 301. 1753.

Common names: Cultivated onion
Treatment appears in FNA Volume 26. Treatment on page 244. Mentioned on page 225, 228.

Bulbs 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, 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, fistulose, inflated below middle, 30–100 cm × 3–20 mm. Umbel 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 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 not known.


Phenology: Flowering Jun–Aug.
Habitat: Disturbed sites adjacent to areas where cultivated
Elevation: 0–500 m

Distribution

Ark., Calif., Kans., La., Mont., Oreg., Tex., Wash., cultivated in Europe, Asia

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.

Selected References

None.

Lower Taxa

None.

"thicker" is not a number."broad" is not a number.

... more about "Allium cepa"
versatile +  and dorsifixed +
cordate +  and linear +
Acute (?) +, Obtuse (?) +  and Acuminate (?) +
Dale W. McNeal Jr. +  and T. D. Jacobsen +
Linnaeus +
whorled +, opposite +  and alternate +
dilated +
not petiolate +
straight +
10 cm100 mm <br />0.1 m <br /> (50 cm500 mm <br />0.5 m <br />) +
fistulose +
4mm;20mm +
conspicuous +
not rhizomatous +
5cm +  and 8cm +
1 +  and 3 +
varying +
3 cm30 mm <br />0.03 m <br /> (10 cm100 mm <br />0.1 m <br />) +
roughened +  and smooth +
quadrate +
Cultivated onion +
Ark. +, Calif. +, Kans. +, La. +, Mont. +, Oreg. +, Tex. +, Wash. +, cultivated in Europe +  and Asia +
0–500 m +
connate-coroniform +  and dilated +
sessile +  and pedicellate +
unisexual +  and bisexual +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
loculicidal +
membranaceous +  and leathery +
Disturbed sites adjacent to areas where cultivated +
paired +, paniculate +  and racemose +
white +  and pink +
persistent +
white +, red +  and yellowish-brown +
crested;3-lobed +
many;several +
spreading +  and erect +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
membranous +
zygomorphic +  and actinomorphic +
Flowering Jun–Aug. +
persistent +
30cm +  and 100cm +
inflated +  and fistulose +
3mm +  and 20mm +
wind-distributed +
1 +  and many +
obovoid +
adnate +  and free +
1 +  and several +
Allium cepa +
species +
persisting +
distinct +
erect +  and more or less spreading +
petal-like +
sepaloid +  and petaloid +
narrower +
compact +  and 500-flowered +
persistent +
9 +, 8 +  and 7 +