Allium cernuum |
Allium nevadense |
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lady's leek, nodding onion |
Nevada onion |
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Bulbs | 2–5+, clustered, often short-rhizomatous at base, rhizome not stout or iris-like, oblong, elongate, 1–3 × 0.8–1.5 cm; outer coats enclosing 1 or more bulbs, grayish or brownish, membranous, minutely striate, cells in regular vertical rows, narrowly elongate, fibers persistent, parallel, few; inner coats white to pink or reddish, cells in regular vertical rows, narrowly elongate. |
1–3, not clustered on stout, primary rhizome, with 0–2 stalked, basal bulbels, ovoid, 1–2 × 0.8–1.5 cm; outer coats enclosing 1 or more bulbs, brown, membranous, usually prominently cellular-reticulate, cells ± transversely elongate, intricately contorted, without fibers; inner coats white or pinkish, cells elongate, intricately contorted. |
Leaves | persistent, green at anthesis, 3–5, basally sheathing, sheaths not extending much above soil level; blade solid, flat, channeled to broadly V-shaped in cross section, 10–25 cm × 1–6 mm, margins entire or denticulate. |
persistent, 1, basally sheathing, sheath not extending much above soil surface; blade solid, terete, 10–20 cm × 1–3 mm. |
Scape | persistent, sometimes 2 or more produced successively from single bulb, usually clustered, nodding, solid, terete or ridged, particularly distally, sometimes flattened and narrowly winged, abruptly recurved near apex, 10–50 cm × 1–3 mm. |
persistent, solitary, erect, ± solid, terete, 5–15 cm × 1–2.5 mm. |
Umbel | persistent, cernuous, loose, 8–35-flowered, hemispheric, bulbils unknown; spathe bracts persistent, 2, 3-veined, lanceolate, ± equal, apex acuminate, beakless. |
persistent, erect, compact, 5–25-flowered, hemispheric, bulbils unknown; spathe bracts persistent, 2–3, 3–7-veined, ovate to lanceolate, ± equal, apex acuminate. |
Flowers | campanulate, 4–6 mm; tepals ± erect, pink or white, elliptic-ovate, ± equal, withering in fruit, margins ± entire, apex ± obtuse, at least outer tepals strongly incurved, midribs not thickened; stamens exserted; anthers yellow; pollen yellow; ovary conspicuously crested; processes 6, flattened, ± triangular, margins entire or toothed; style exserted, linear, ± equaling stamens; stigma capitate, scarcely thickened, unlobed; pedicel 6–25 mm, becoming stouter in fruit, elongating and bending abruptly upward from near point of attachment. |
stellate, 7–12 mm; tepals spreading, white or pinkish white with dark pink midveins, lanceolate to ovate, ± equal, becoming papery in fruit, margins entire, apex acute to acuminate; stamens included; anthers purple; pollen yellow; ovary crested; processes 6, prominent, ± triangular, margins entire to notched or shallowly toothed; style linear, equaling stamens; stigma capitate, scarcely thickened, unlobed; pedicel 8–16 mm. |
Seed | coat dull or shining; cells smooth, minutely roughened, or each with minute, central papilla. |
coat dull; cells minutely roughened. |
2n | = 14. |
= 14, 28. |
Allium cernuum |
Allium nevadense |
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Phenology | Flowering Jul–Oct. | Flowering Apr–Jun. |
Habitat | Widely distributed on moist soils in mountainous and cool regions | Sandy, rocky, or occasionally clay soils on desert plains and hillsides |
Elevation | 600–3500 m (2000–11500 ft) | 1400–1700 m (4600–5600 ft) |
Distribution |
AL; AR; AZ; CO; DC; GA; IA; ID; IL; IN; KY; MD; MI; MN; MO; MT; NC; NE; NM; NY; OH; OR; PA; SC; SD; TN; TX; UT; VA; WA; WI; WV; WY; AB; BC; ON; SK; Mexico
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AZ; CA; CO; ID; NV; OR; UT
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Discussion | Allium cernuum is the most widespread North American species of the genus. It is closely related to A. stellatum, and the character commonly used to differentiate them has been umbel orientation. In both species, the inflorescence is nodding in bud, but in A. stellatum it usually becomes erect by anthesis. In A. cernuum the peduncle remains permanently recurved near the apex, although the inflorescence may sometimes become erect overall, or nearly so. While this character is helpful in identification, an almost exclusive reliance on it (even by one of the present authors in his youth) has obscured other clearer distinctions between the species and has confused their geographic ranges. More reliable characters for differentiating these species are bulb shape (elongate in A. cernuum, ovoid in A. stellatum) and perianth shape (campanulate in A. cernuum, stellate in A. stellatum). Unfortunately, perianth shape is often difficult to see in herbarium specimens. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 26, p. 247. | FNA vol. 26, p. 248. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | A. allegheniense, A. oxyphilum, A. recurvatum | A. nevadense var. macropetalum |
Name authority | Roth: Arch. Bot. (Leipzig) 1: 40. (1798) | S. Watson: Botany (Fortieth Parallel), 351, plate 38, figs. 1–3. (1871) |
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