Allium rhizomatum |
Allium rotundum |
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spreading wild onion |
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Bulbs | solitary, not basally clustered, replaced annually by new bulbs borne terminally on rhizome; rhizomes 1–3, conspicuous, slender, 2–3 cm, scaly; parent bulbs persisting, often not collected, oblique-ovoid, 1–2.5 × 1 cm; outer coats enclosing parent bulbs, grayish, lacking cellular reticulation, membranous, without fibers; inner coats white or hyaline, cells obscure, ± quadrate. |
1–50+, ovoid, 0.2–1.5 × 0.2–1 cm; outer coats surrounding numerous, very dark purple bulbels, usually white or greenish, membranous, sometimes breaking into ± parallel, fibrous strips; inner coats white, cells obscure, quadrate. |
Leaves | persistent, green at anthesis, 2–3, basally sheathing, sheaths not extending much above soil surface; blade solid, flat, not falcate, 20–35 cm × 2–3 mm, margins entire. |
persistent, 2–5, sheathing 1/3–1/2 scape; blade solid, flat or channeled, carinate, 15–40 cm × 2–5(–7) mm, margins entire. |
Scape | solitary, erect, solid, terete, 20–30 cm × 1–3 mm. |
persistent, solitary, erect, ± solid, 25–90 cm × 1–4 mm. |
Umbel | persistent, erect, loose, 5–15(–22)-flowered, globose to hemispheric, bulbils unknown; spathe bracts persistent, 2, 3-veined, ovate to lance-ovate, ± equal, apex acute. |
persistent, erect, very dense, 80–200-flowered, globose, bulbils unknown; spathe bracts caducous, 2, 7–12-veined, lanceolate, ± equal, apex narrowed to beak, beak to 2 cm. |
Flowers | stellate, 6–9 mm; tepals erect, pink with purplish or pinkish midveins, oblong to lanceolate, slightly carinate basally, ± equal, becoming papery in fruit, margins entire, apex acute to acuminate; stamens included; anthers yellow or pink; pollen yellow or white; ovary crestless, 3-grooved with thickened ridge on either side of groove; style linear, shorter than stamens; stigma capitate, scarcely thickened, unlobed; pedicel 10–20(–50) mm. |
campanulate, 4–7 mm; tepals erect, purple, or inner with broad whitish margins and purple midvein, oblong to ovate, ± equal, becoming keeled and ± rigid in fruit, margins entire, apex acute to obtuse; stamens included; filaments: outer unlobed, inner with 2 prominent teeth on either side of anther, teeth 2–3 times anther-bearing portion, usually papillose to ciliate; anthers yellow or purple; pollen light yellow to white; ovary crestless; style linear, ± equaling anther-bearing portion of stamens; stigma capitate, unlobed; pedicels 5–30 mm, outer much shorter than inner. |
Seed | coat shining; cells smooth. |
coat dull; cells each with central papilla. |
2n | = 28. |
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Allium rhizomatum |
Allium rotundum |
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Phenology | Flowering Jul–Sep. | Flowering May–Jul. |
Habitat | Dry, usually grassy areas | Disturbed fields and roadsides |
Elevation | 1200–2200 m (3900–7200 ft) | |
Distribution |
AZ; NM; TX; Mexico
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MI; c Europe; s Europe [Introduced in North America] |
Discussion | Allium rhizomatum has often been included within the Mexican species A. glandulosum. This reduction is unwarranted. The perianth of A. rhizomatum is pale, with the color mainly confined to the midribs. Additionally, the species can be distinguished by its 3-lobed, apically 3-grooved ovary and lack of sepal glands. Allium glandulosum has a red perianth, an apically rounded ovary, and sepal glands. The nectar produced from these glands does not show in herbarium specimens. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Allium rotundum is native to central and southern Europe. It is reported as established in southern Michigan, and is to be expected elsewhere in the Great Lakes region. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 26. | FNA vol. 26, p. 244. |
Parent taxa | Liliaceae > Allium | Liliaceae > Allium |
Sibling taxa | ||
Name authority | Wooton & Standley: Contr. U.S. Natl. Herb. 16: 114. (1913) | Linnaeus: Sp. Pl. ed. 2, 1: 423. (1762) |
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