Sp. Pl. 1: 294. 1753.


Gen. Pl. ed. 5, 143. 1754.

Common names: Onion
Etymology: Latin, classical name for garlic
Treatment appears in FNA Volume 26. Treatment on page 224. Mentioned on page 53, 55, 225, 259, 334, 336.
FNA26 Plate 031.jpegAllium canadense var. canadense
Allium canadense var. mobilense
Allium geyeri var. geyeri
Allium geyeri var. tenerum
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
FNA26 Plate 032.jpegAllium drummondii
Allium schoenoprasum
Allium textile
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
FNA26 Plate 033.jpegAllium brevistylum
Allium haematochiton
Allium cernuum
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
... further results

Herbs, perennial, scapose, from tunicate bulbs, with onion odor and taste. Bulbs solitary or clustered, dividing at base, or on rhizomes, reforming annually; outer coats generally brown or gray, smooth, fibrous, or with cellular reticulation (generally important in identification); inner coats membranous. Leaves generally withering from tip by anthesis, usually persistent, 1–12, basal; blade usually linear, terete, channeled, or flat (carinate in A. sativum, A. praecox, A. tuberosum, A. rotundum, A. neapolitanum, A. triquetrum, A. unifolium, and A. lacunosum), straight or ± falcate (coiled or circinate in A. nevadense and A. atrorubens), broader in A. victorialis and A. tricoccum, not petiolate (except in A. tricoccum and A. victorialis). Scape usually persistent, terete or flattened. Inflorescences umbellate, flowering centripetally (centrifugally in A. schoenoprasum), sometimes replaced totally or partially by bulbils, subtended by spathe bracts; bracts conspicuous, ± fused, usually 3+-veined, equaling pedicel except in some introduced species, membranous. Flowers erect (pendent in A. triquetrum); tepals 6, in 2 similar whorls, ± distinct, petallike, usually becoming becoming dry and persisting; stamens 6, epipetalous; filaments in all but 1 native species broad at base, fused into ring (some introduced species and A. victorialis appendaged), linear, generally glabrous (A. rotundum and A. hoffmanii papillose to ciliate proximally); anthers and pollen variously colored; ovary superior, 3-lobed, sometimes crested with processes, 3-locular, usually 2 ovules per locule (6–8 in A. nigrum), crest processes 3 or 6, smooth except in A. haematochiton, A. sharsmithiae, and A. lacunosum; style 1; stigma capitate to ± 3-lobed; pedicel erect or spreading (lax in A. triquetrum). Fruits capsular, dehiscence loculicidal. Seeds black, obovoid, finely cellular-reticulate, cells smooth or minutely roughened, with 1–8 papillae, without caruncle except in A. triquetrum. x = 7, 8, 9.


Mostly Northern Hemisphere


Species 550–700 (96 in the flora).

As with many other genera in the Liliaceae sensu lato, Allium has been segregated into a separate family, Alliaceae, by most recent authors (R. Dahlgren et al. 1985; K. Rahn 1998; A. L. Takhtajan 1997; R. F. Thorne 1992).

Old World species of Allium are generally placed in subgenera and sections. Attempts to treat New World species similarly have gained less acceptance. H. P. Traub (1972) recognized subg. Amerallium, encompassing all of the x = 7 North American members of the genus. P. Hanelt (1992) placed the Old World x = 7 species also in that subgenus, which includes all but three of the North American species (A. schoenoprasum, A. tricoccum, and A. victorialis), which have x = 8. These latter species have been placed in subg. Rhizirideum (P. Hanelt 1992). Resolution of the problematic subgeneric and sectional relationships among Old and New World species will require much more extensive molecular and phylogenetic analysis of the genus.

The characters used in the construction of the following key are the best that have been discovered for this purpose. Many of these are subject to sometimes rather wide variation. It is anticipated, therefore, that it can be used successfully only with considerable understanding of the natural units involved, their distribution, and comparison with descriptions and accurately named specimens.

The Allium bulb consists of a series of leaf bases, some with blades, others without, surrounding an apical meristem. The leaf bases are replaced annually as the meristem forms a new (renewal) bulb. Often the meristem will branch, resulting in two or more bulbs being formed from a single parent bulb (increase bulbs). In addition several types of rhizomes are formed in Allium. In some cases (e.g., A. validum) bulbs form atop a thick, iris-like rhizome that produces new bulbs in succeeding years. In other cases (e.g., A. bolanderi, A. campanulatum, and A. unifolium) each bulb produces one or more rhizomes that in turn produce a terminal renewal or increase bulb. There is variation even in this type of rhizome. In some species (e.g., A. bolanderi and A. unifolium) the bulb producing the rhizomes disappears during the development of the rhizomes and new bulbs except for the roots, which remain active until the new bulbs mature and become dormant. In others (e.g., A. campanulatum) the bulb produces a number of very short rhizomes around the roots, each of which develops a very small terminal bulbel. At the same time, the parent bulb remains intact and produces a renewal bulb, or may divide to produce two or more large increase bulbs. As a result, specimens with this type of rhizome will have one or more large bulbs with a number of much smaller bulbels among the roots.

The underground parts of Allium are often critical for successful identification, and every effort should always be made to collect them. The “dirty” brown or gray coats surrounding the bulbs are the only source for the cellular-reticulation patterns referred to in the key. These should be carefully collected and preserved as part of any specimen.

Several Old World species (Allium ampeloprasum Linnaeus, A. cepa Linnaeus, A. oleraceum Linnaeus, A. sativum Linnaeus, A. nigrum Linnaeus), grown as foodstuffs or ornamentals, may be encountered and are certainly represented in North American herbaria. For this reason, these species have been included in the key. Some do not reproduce by seeds and probably should not be considered as truly naturalized in our flora, although they may persist for long periods at or near places where they have been planted. Additionally, over 52 species contained in this treatment are considered choice garden plants and are readily available through catalogues and garden centers. Locally, these species and possibly others grown as garden plants may escape and become established. It is inevitable, therefore, that numerous specimens of these escapees will be represented in North American herbaria and may muddy the boundaries of what is regarded to be the natural distribution. We have attempted in all cases to map what we consider to be the natural ranges of these species, based on the specimens examined over the years. Material falling outside these ranges may include these escapees and should be suspect.

Selected References


Lower Taxa

Allium aaseae, Allium abramsii, Allium acuminatum, Allium ampeloprasum, Allium amplectens, Allium anceps, Allium atrorubens, Allium bigelovii, Allium bisceptrum, Allium bolanderi, Allium brandegeei, Allium brevistylum, Allium burlewii, Allium campanulatum, Allium canadense, Allium cepa, Allium cernuum, Allium columbianum, Allium constrictum, Allium coryi, Allium cratericola, Allium crenulatum, Allium crispum, Allium cuthbertii, Allium denticulatum, Allium diabolense, Allium dichlamydeum, Allium dictuon, Allium douglasii, Allium drummondii, Allium elmendorfii, Allium falcifolium, Allium fibrillum, Allium fimbriatum, Allium fistulosum, Allium geyeri, Allium gooddingii, Allium haematochiton, Allium hickmanii, Allium hoffmanii, Allium howellii, Allium hyalinum, Allium jepsonii, Allium kunthii, Allium lacunosum, Allium lemmonii, Allium macropetalum, Allium macrum, Allium madidum, Allium membranaceum, Allium monticola, Allium munzii, Allium neapolitanum, Allium nevadense, Allium nevii, Allium nigrum, Allium obtusum, Allium oleraceum, Allium paniculatum, Allium parishii, Allium parryi, Allium parvum, Allium passeyi, Allium peninsulare, Allium perdulce, Allium platycaule, Allium plummerae, Allium praecox, Allium punctum, Allium rhizomatum, Allium robinsonii, Allium rotundum, Allium runyonii, Allium sanbornii, Allium sativum, Allium schoenoprasum, Allium scilloides, Allium serra, Allium sharsmithiae, Allium shevockii, Allium simillimum, Allium siskiyouense, Allium speculae, Allium stellatum, Allium textile, Allium tolmiei, Allium tribracteatum, Allium tricoccum, Allium triquetrum, Allium tuberosum, Allium tuolumnense, Allium unifolium, Allium validum, Allium victorialis, Allium vineale, Allium yosemitense


1 Leaf blade flat, 15–90 mm wide, (tapering to base or distinctly petiolate). > 2
1 Leaf blade flat, channeled, or ± terete, never more than 30 mm wide, (never petiolate). > 3
2 Leaves ephemeral, usually absent at anthesis; e North America. Allium tricoccum
2 Leaves present at anthesis; Attu and Unalaska islands, Alaska. Allium victorialis
3 Flowering pedicels mostly or completely replaced by bulbils. > 4
3 Flowering pedicels floriferous, bulbils almost unknown. > 9
4 Outer bulb coats persisting as fibrous reticulum; leaf sheaths not extending more than 1/4 scape; spathe bract beakless or beak much shorter than base. > 5
4 Outer bulb coats membranous, if with fibers these not forming reticulum; leaf sheaths extending to midscape or above; spathe bract with beak equaling or longer than base. > 6
5 Ovary, when present, crestless; spathe bracts 3–7-veined; east of 103rd meridian. Allium canadense
5 Ovary, when present, obscurely crested with 6, low, central processes; spathe bracts 1-veined; west of 105th meridian. Allium geyeri
6 Spathe bract 1, caducous. > 7
6 Spathe bracts 2–5, persistent. > 8
7 Bulbs 1–2 cm diam.; leaf blade 2–4 mm diam., cylindric or filiform, not carinate, hollow below middle. Allium vineale
7 Bulbs (1.5–)3–8 cm diam.; leaf blade 5–20 mm wide, flat, carinate, solid. Allium sativum var. sativum
8 Spathe bracts 2–5, 4–9-veined, beak to 20 cm. Allium oleraceum
8 Spathe bracts 3–5, 2–3-veined, beak to 10 cm. Allium ampeloprasum
9 Outer bulb coats persisting as fibrous reticulum. > 10
9 Outer bulb coats membranous to chartaceous, with or without distinct cellular markings (reticulation); without fibers or with some parallel fibers. > 24
10 Ovary usually crestless; if obscurely crested, with 3 or 6 processes; east of 103rd meridian. > 11
10 Ovary usually crested with 3 or 6 processes; if crestless, from west of 105th meridian. > 17
11 Spathe bracts usually 1-veined. > 12
11 Spathe bracts 3–7-veined. > 13
12 Spaces between bulb coat fibers filled in proximal 1/2 bulb; tepals white, pink, or red, rarely greenish yellow; central plains from n Mexico to Nebraska. Allium drummondii
12 Spaces between bulb coat fibers open; tepals yellow; w Texas. Allium coryi
13 Umbel compact; pedicels much shorter than flowers. Allium schoenoprasum
13 Umbel loose; pedicels longer than flowers. > 14
14 Flowers substellate to urceolate-campanulate, ultimately withering somewhat and exposing capsule; reticula of bulbs finely or only moderately coarsely meshed. > 15
14 Flowers urceolate, permanently investing capsule; reticula of bulbs usually very coarsely meshed. > 16
15 Bulbs 1–3, narrowly cylindric, attached to ± horizontal primary rhizome, often missing or not visible on herbarium specimens; leaf blade carinate; cells of seed coat smooth, shiny; occasional introduction. Allium tuberosum
15 Bulbs 1–4+, ovoid, not attached to rhizome; leaf blades not carinate, channeled; cells of seed coat each with minute, central papilla; native east of 103rd meridian. Allium canadense
16 Flowering bulbs with cluster of stalked, basal bulbels; cells of innermost bulb coats contorted, with sinuous walls; extreme s Texas. Allium runyonii
16 Flowering bulbs without basal bulbels; cells of innermost bulb coats vertically elongate, without sinuous walls; w Texas and e New Mexico to c South Dakota. Allium perdulce
17 Ovary and capsule conspicuously crested with 6 contorted or horizontally spreading, ± lateral processes; tepals widely spreading to reflexed, se United States. > 18
17 Ovary crested with 6 ± erect, often obscure central processes; tepals erect to widely spreading; w North America. > 19
18 Spathe bracts usually 5–7-veined; ovary crests conspicuously contorted; tepals spreading to reflexed. Allium cuthbertii
18 Spathe bracts 1-veined; ovary crests flattened, horizontally spreading, not contorted; tepals widely spreading. Allium speculae
19 Leaves 3+ per scape; cells of seed coat each with minute, central papilla. > 20
19 Leaves usually 2 per scape; cells of seed coat ± smooth, with or without central papillae. > 22
20 Bulbs often short-rhizomatous basally; spathe bracts 3–5-veined; ovary conspicuously crested with 6 flattened, lacerate central processes; tepals spreading or reflexed, withering in fruit, not investing capsule. Allium plummerae
20 Bulbs not short-rhizomatous; spathe bracts usually 1-veined; ovary obscurely crested with 6 rounded central processes; tepals erect, not withering in fruit, permanently investing capsule. > 21
21 Leaf blade flat, ± falcate, usually 3–6 mm wide; Box Elder County, Utah. Allium passeyi
21 Leaf blade channeled, ± straight, usually less than 5 mm wide; widespread, n Great Plains and w North America. Allium geyeri
22 Spathe bracts 3–5-veined; tepals becoming papery in fruit, midrib scarcely thickened, not investing capsule; ovary usually conspicuously crested with 6 flattened central processes, often to 2 mm. Allium macropetalum
22 Spathe bracts 1-veined; tepals becoming callous-keeled, permanently investing capsule; ovary inconspicuously crested with 6 rounded central processes, to 1 mm. > 23
23 Leaf blade flat, ± falcate, usually 3–6 mm wide; cells of seed coat with minute central papilla; Box Elder County, Utah. Allium passeyi
23 Leaf blade semiterete, channeled, ± straight, usually 1–3(–5) mm wide; cells of seed coat smooth; n Great Plains and w North America. Allium textile
24 Scape fistulose, 3–25 mm diam., not flattened and winged; leaves 2–10, blade flat and solid, or fistulose. > 25
24 Scape solid, exceeding 5 mm wide only if flattened and winged; leaves 1–several, leaf blade solid. > 29
25 Leaf blade flat, solid. > 26
25 Leaf blade fistulose. > 27
26 Leaves not or scarcely sheathing base of scape. Allium nigrum
26 Leaves sheathing 1/3–1/2 scape. Allium ampeloprasum
27 Bulbs 1–3, to 10 cm diam., ± globose, not rhizomatous; leaf blade semicircular in cross section; occasional escape from cultivation. Allium cepa
27 Bulbs 1–2, 5 cm diam., cylindric, clustered on short rhizome (this often missing or not visible on herbarium specimens); leaf blade circular in cross section; native or introduced. > 28
28 Flowers 8–18 mm; tepals lilac to pale purple; native or introduced. Allium schoenoprasum
28 Flowers 6–9 mm; tepals pale yellowish white; introduced. Allium fistulosum
29 Leaves (3–)5–40 mm wide, basal sheaths extending 1/3–1/2 scape. > 30
29 Leaves 1–25 mm wide, basal sheaths never extending much above soil level. > 31
30 Filaments unappendaged; leaf blade terete to semiterete; bulbels, if present, light brown. Allium paniculatum
30 Inner filaments appendaged with prominent tooth on each side of anther; leaf blade flat, channeled; bulbels very dark purple. Allium rotundum
31 Bulbs oblong, elongate, or ovoid, clustered on stout, primary rhizome, or short-rhizomatous; bulb coats membranous or chartaceous, finely striate with narrow, vertically elongate cells. > 32
31 Bulbs ovoid to subglobose, not clustered on stout, primary rhizome; rhizomes, if present, secondary, arising from bulbs, ± slender, terminated by new bulbs; bulb coats without reticulation or with ± isodiametric or transversely elongate cells that are sometimes intricately contorted. > 37
32 Bulbs on stout, iris-like rhizome; ovary crestless. > 33
32 Bulbs short-rhizomatous at base, rhizome not stout and iris-like; ovary strongly crested with 6 processes. > 35
33 Tepals elliptic, apex obtuse; stamens ± equaling tepals; ec Arizona and adjacent New Mexico, and Santa Catalina Mountains, s Arizona. Allium gooddingii
33 Tepals narrowly lanceolate to lanceolate, apex acuminate; stamens much shorter than tepals or definitely exserted; widespread in w North America, not occurring in Arizona. > 34
34 Stamens and style exserted; stigma capitate; Cascades and Sierras e to ne Nevada, e Oregon, w Idaho. Allium validum
34 Stamens and style ca. 1/2 tepals; stigma 3-lobed; Rocky Mountains from c Montana and ne Idaho to Wyoming, ne Utah, Colorado, and New Mexico. Allium brevistylum
35 Stamens and styles included; outer bulb coats ± reddish brown, inner coats deep red to white; ovary crested with 6 short, rounded, densely papillose processes. Allium haematochiton
35 Stamens and styles exserted; outer bulb coats gray or brown, inner coats white to pink or reddish; ovary crested with 6 flattened, ± triangular processes, margins entire or toothed. > 36
36 Flowers campanulate; tepals ± erect; scape nodding. Allium cernuum
36 Flowers stellate; tepals spreading; scape erect, or, if nodding at anthesis, becoming erect. Allium stellatum
37 Leaf 1 per scape; leaf blade terete; ovary prominently crested with 6 ± triangular processes. > 38
37 Leaves usually 2 or more, if 1, blade flattened or broadly channeled; ovary crestless or variously crested. > 55
38 Stigma unlobed or minutely 3-lobed, lobes ± stout, erect or spreading. > 39
38 Stigma distinctly 3-lobed, lobes often slender and recurved. > 43
39 Scape 18–60 cm; flowers 5–9 mm; tepals unequal, inner whorl 1/4–1/3 longer than outer, margins entire or irregular to erose; stamens exserted. Allium sanbornii
39 Scape less than 25 cm; flowers 7–20 mm; tepals ± equal, margins entire; stamens included. > 40
40 Outer bulb coat reticulate with ± elongate, contorted meshes. Allium nevadense
40 Outer bulb coat lacking reticulation, or meshes very indistinct, square or polygonal. > 41
41 Pedicels slender, longer than flowers; flowers 8–12 mm. Allium atrorubens
41 Pedicels stout, generally shorter than flowers; flowers 12–20 mm. > 42
42 Tepals lanceolate to lance-linear, apex acute; lacking stalked, basal increase bulbs; rocky, sandy desert slopes, s California to w Arizona. Allium parishii
42 Tepals lance-linear to lanceolate, apex long-acuminate; with 1–2 stalked basal increase bulbs; alpine ridges and talus, s California mountains. Allium monticola
43 Stamens equaling tepals or exserted. > 44
43 Stamens included. > 45
44 Tepals unequal, inner 1/3–1/2 longer than outer. Allium sanbornii
44 Tepals ± equal. Allium howellii
45 Tepal (at least inner whorl) margins denticulate to erose. > 46
45 Tepal margins all ± entire. > 48
46 Scape 25–40 cm. Allium jepsonii
46 Scape 5–20 cm. > 47
47 Outer bulb coats reddish brown; tepals erect, ± straight at tip; inner whorl margins denticulate. Allium denticulatum
47 Outer bulb coats brown to gray; tepals erect, ± spreading-reflexed at tip; inner whorl margins denticulate to erose. Allium abramsii
48 Margins of ovarian crest processes entire or notched at tip, outer margins sometimes irregular but never dentate or laciniate. > 49
48 Margins of ovarian crest processes dentate to laciniate. > 52
49 Flowers 10–18 mm; tepals maroon or deep reddish purple. > 50
49 Flowers 6–9 mm; tepals white to pink, darkening in age. > 51
50 Tepals deep reddish purple, all reflexed at tip; Mount Hamilton Range, c California. Allium sharsmithiae
50 Tepals maroon, outer curled back at tip, inner reflexed; Spanish Needle Peak, s Sierra Nevada, and Horse Canyon, Tehachapi Mountains, California. Allium shevockii
51 Inflorescence loose; pedicels flexuous in fruit; tepals lanceolate to lance-ovate, apex acuminate. Allium parryi
51 Inflorescence compact; pedicels straight; tepals ovate to nearly round, apex obtuse (rarely acute) to shallowly emarginate. Allium munzii
52 Tepals deep reddish purple, erect, usually conspicuously recurved at tip. Allium fimbriatum
52 Tepals white or flushed to pale lavender with darker midveins, spreading or erect, not conspicuously recurved at tip. > 53
53 Flowers usually 6–12 mm. Allium fimbriatum
53 Flowers usually 6–8(–10) mm. > 54
54 Scape 25–50 cm; tepals spreading from base; serpentine soil, Rawhide Hill and Red Hills, foothills of Sierra Nevada, c California. Allium tuolumnense
54 Scape 7–20(–30) cm; tepals erect; serpentine clay soils, s Coast Ranges and w Transverse Ranges, California. Allium diabolense
55 Bulbs generally with numerous increase bulbs, these much smaller than parent bulb, enclosed by bulb coats, in basal cluster or on threadlike rhizomes to 10 cm. > 56
55 Increase bulbs absent or 1–4, ± equaling parent bulbs, enclosed by parental bulb coats, never appearing as basal cluster, not rhizomatous or rhizomes 2+ mm thick (not threadlike). > 60
56 Ovary crestless or obscurely crested with 3 low central processes. > 57
56 Ovary prominently crested with 6 triangular central processes, margins finely papillose or denticulate. > 58
57 Larger bulbs each with cluster of bulbels surrounding roots; s Texas. Allium elmendorfii
57 Larger bulbs each with cluster of small, basal bulbels on one side; ne Oregon and wc Idaho. Allium madidum
58 Leaves usually beginning to wither from tip by anthesis; tepals rigid (not papery), ± shiny in fruit, strongly involute at tip, carinate. Allium campanulatum
58 Leaves usually green at anthesis; tepals papery (not rigid and shiny) in fruit, not strongly involute, not carinate. > 59
59 Tepals ovate to elliptic, apex acute to acuminate; foothills of Sierra Nevada, n, c California. Allium membranaceum
59 Tepals lanceolate, apex acuminate; Sierra Nevada, California, and intermountain region n to Oregon, Idaho. Allium bisceptrum
60 Leaf blade channeled to subterete, if flat, not falcate. > 61
60 Leaf blade flat or broadly channeled, if flat, ± falcate. > 79
61 Bulb coats lacking reticulation or reticulum delicate, very obscure under hand lens. > 62
61 Bulb coats obviously reticulate with prominent meshes under hand lens. > 68
62 Bulbs ovoid to subglobose; rhizomes absent, renewal bulbs formed within coats of parent bulb; native or introduced. > 63
62 Bulbs oblique or oblique-ovoid, renewal bulbs borne terminally on rhizomes outside coats of parent bulbs; native. > 65
63 Scape terete throughout, 1–3 mm diam.; leaf blade 1–3 mm wide; native to w Texas to se Arizona. Allium kunthii
63 Scape triquetrous, 2-edged or slightly winged proximally, if terete only proximally so, 1–10 mm wide; introduced in California and Oregon near the Pacific coast. > 64
64 Umbel erect, ± hemispheric; flowers ± erect; tepals broadly elliptic, apex obtuse. Allium neapolitanum
64 Umbel lax, ± 1-sided; flowers pendent; tepals lanceolate, apex acute. Allium triquetrum
65 Rhizomes conspicuous, 2 cm or more, including renewal bulbs. > 66
65 Rhizomes inconspicuous, 2 cm or less, including renewal bulb. > 67
66 Rhizomes smooth, parent bulb disappearing by anthesis except for still-functional roots and bulb coat; leaf blade broadly concave-convex or ± flattened, carinate; tepals obovate to ovate, apex acute to obtuse or emarginate; Coast Ranges, California, Oregon. Allium unifolium
66 Rhizomes scaly, sometimes absent, often missing in herbarium specimens, parent bulb persisting after anthesis; leaf blade flat, not carinate; tepals lanceolate to oblong, apex acute to acuminate; trans- Pecos Texas to se Arizona. Allium rhizomatum
67 Tepals erect, red-purple, rarely pure white, at least inner tepal margins serrulate; nw California, sw Oregon. Allium bolanderi
67 Tepals ± spreading, white to pale pink, margins entire; w Texas to se Arizona. Allium kunthii
68 Cells of outer bulb coat square or polygonal. > 69
68 Cells of bulb coat transversely elongate, V-shaped, arranged in ± vertical rows, forming herringbone pattern, or ± contorted. > 72
69 Ovary with 6 prominent, flat, ± triangular crest processes. Allium bigelovii
69 Ovary with 3 or 6 minute, rounded crest processes, or crest obscure. > 70
70 Flowers 4–9 mm; tepals erect or spreading from base, margins entire. Allium lacunosum
70 Flowers 8–16 mm; tepals spreading at tip, inner tepal margins denticulate. > 71
71 Bulb forming 1–3 renewal bulbs borne terminally on rhizomes outside coats of parent bulb; parent bulb disappearing by anthesis except for still-functional roots and shriveled bulb coats; near Weller Butte, Blue Mountains, se Washington. Allium dictuon
71 Bulbs not forming rhizomes, renewal bulbs formed within coats of parent bulb; widespread w of Rocky Mountains. Allium acuminatum
72 Cells of bulb coat in wavy, transverse rows, forming indistinct herringbone pattern or ± contorted; tepals spreading, ± equal. > 73
72 Cells of bulb coat in sharply serrate, transverse rows, forming distinct herringbone pattern; tepals erect, inner shorter, narrower. > 76
73 Scape (3–)5–15(–17) cm; umbel persistent; tepals erect, not connivent over capsule in fruit. Allium hickmanii
73 Scape 15–60 cm; umbel shattering, each flower with its pedicel falling as unit; tepals connivent over capsule in fruit. > 74
74 Ovary crested with 6 ± rectangular lateral processes; umbel compact; pedicel 0.7–2 times perianth. Allium amplectens
74 Ovary crestless or crested with 3 minute, 2-lobed central processes; umbel loose; pedicel 1.5–4 times perianth. > 75
75 Leaf blade to 10 mm wide, channeled or flattened, carinate; inner bulb coats white; tepals becoming papery (not hyaline) after anthesis. Allium praecox
75 Leaf blade 1–3 mm wide, channeled or subterete, not carinate; inner bulb coats light yellow or white; tepals becoming hyaline (not papery) after anthesis. Allium hyalinum
76 Tepals connivent over capsule in fruit, not rigid; umbel shattering in fruit, each flower with its pedicel falling as a unit. Allium serra
76 Tepals not connivent over capsule, rigid in fruit; umbel persistent. > 77
77 Leaves 3–6, blade arcuate to tortuous; umbel compact; pedicels 5–20 mm; sea cliffs, n, c California. Allium dichlamydeum
77 Leaves 2–3, blade straight to arcuate; umbel loose; pedicels 10–40 mm; not on sea cliffs, California Floristic Province, extending south in coastal ranges. > 78
78 Inner tepal margins denticulate, crisped. Allium crispum
78 Inner tepal margins entire to denticulate, never crisped. Allium peninsulare
79 Scape and leaves persisting after seeds mature or on pressing, or only tardily deciduous. > 80
79 Scape and leaves forming abcission layer at soil surface and deciduous when seeds mature, also frequently breaking at soil surface after pressing. > 86
80 Stamens much shorter than tepals. > 81
80 Stamens equaling tepals or exserted. > 82
81 Bulb coat cellular-reticulate with elongate, ± obscure, intricately contorted cells (resembling Allium madidum, but never with cluster of basal bulbels). Allium fibrillum
81 Bulb coat cellular-reticulate with ± narrowly hexagonal, transversely elongate cells. Allium brandegeei
82 Scape expanded proximal to inflorescence; leaf blade (2–)5–8 mm wide. Allium columbianum
82 Scape thickest immediately proximal to inflorescence; leaf blade 1–5(–15) mm wide. > 83
83 Scape constricted just proximal to inflorescence, then expanded; leaf blade 1–3(–5) mm wide. Allium constrictum
83 Scape not expanded proximal to inflorescence; leaf blade 2–5(–15) mm wide. > 84
84 Leaf blade usually more than 5 mm wide, flat; umbel 25–50-flowered; spathe bracts 3. Allium douglasii
84 Leaf blade 2–3 mm wide, flat to channeled; umbel 10–30-flowered; spathe bracts 2. > 85
85 Bulb coat with quadrate to polygonal reticulations; leaf blade ± equaling scape. Allium nevii
85 Bulb coat without reticulations or with 2–3 rows of ± quadrate cells just distal to roots; leaf blade exceeding scape. Allium macrum
86 Outer bulb coats cellular-reticulate throughout (often obscurely so in A. aaseae and A. simillimum). > 87
86 Outer bulb coats not cellular-reticulate or with 2–3 rows of cells just distal to roots. > 93
87 Bulb coats obscurely cellular-reticulate with ± contorted cells; tepal margins denticulate to erose. > 88
87 Bulb coats ± prominently cellular-reticulate; tepal margins entire. > 89
88 Tepals white with greenish or reddish veins, sometimes flushed pink; anthers purple or mottled purple and white; pollen white or gray. Allium simillimum
88 Tepals bright pink, rarely white; anthers yellow; pollen yellow. Allium aaseae
89 Bulb coats reticulate, cells irregularly arranged, ± polygonal, rectangular, or transversely elongate, ± curved. > 90
89 Bulb coats reticulate, cells arranged in ± regular vertical rows, narrowly hexagonal to rectangular, transversely elongate. > 91
90 Cells of bulb coat irregularly arranged, ± transversely elongate, curved; Tuolumne County, c California. Allium tribracteatum
90 Cells of bulb coat irregularly arranged or in ± regular vertical rows, polygonal or ± rectangular; Sierra Nevada, California, and Nevada. Allium obtusum
91 Tepals linear-lanceolate. Allium anceps
91 Tepals oblanceolate to ovate. > 92
92 Scape 3–10 cm; pedicel ± equaling perianth. Allium punctum
92 Scape 15–20 cm; pedicel 2–3 times perianth. Allium lemmonii
93 Scape terete or ± compressed, not winged. > 94
93 Scape flattened, 2-edged or usually winged distally. > 99
94 Stamens well included. > 95
94 Stamens ± equaling tepals or exserted. > 96
95 Leaf blade strongly falcate; umbel mostly 5–10-flowered. Allium parvum
95 Leaf blade linear or weakly falcate; umbel 20–30-flowered. Allium cratericola
96 Leaves 2 per scape. > 97
96 Leaf 1 per scape. > 98
97 Leaf blade ± equaling to 2 times scape; wc Idaho. Allium tolmiei
97 Leaf blade much longer than scape; c Sierra Nevada, California. Allium yosemitense
98 Filaments papillose proximally. Allium hoffmanii
98 Filaments smooth proximally. Allium burlewii
99 Bulbs oblique or oblique-ovoid, renewal bulbs borne terminally on rhizomes outside coats of parent bulb; parent bulb disappearing by anthesis except for still-functional roots and shriveled bulb coat. > 100
99 Bulbs ovoid to subglobose, rhizomes absent, renewal bulbs formed within coats of parent bulb; parent bulbs persistent. > 101
100 Pedicel ± equaling perianth; ovary obscurely 3-crested; barren, bald summits w of Cascade Mountains from Vancouver Island to sw Oregon, also at Jefferson Park, Oregon, and in Wenatchee Mountains, c Washington. Allium crenulatum
100 Pedicel 2–3 times perianth; ovary prominently 6-crested; mountains and scablands e of Cascade Mountains, Oregon. Allium tolmiei
101 Tepals narrowly lanceolate, apex long-acuminate; stamens exserted. Allium platycaule
101 Tepals lanceolate to ovate or elliptic, apex obtuse to acuminate; stamens included. > 102
102 Flowers 9–15 mm; tepal apex long-acuminate, inner margins usually denticulate. Allium falcifolium
102 Flowers 6–10(–12) mm; tepal apex obtuse to acute, or ± involute in age and appearing acuminate, inner margins denticulate or not. > 103
103 Inner bulb coats usually pink or red; inner tepal margins sometimes ± denticulate; Siskiyou Mountains of nw California and sw Oregon. Allium siskiyouense
103 Inner bulb coats white; inner tepal margins entire; w United States, e of Sierra–Cascade axis. > 104
104 Tepals becoming rigid (not papery), carinate in fruit. > 105
104 Tepals becoming papery (not rigid), not carinate in fruit. > 106
105 Tepals lanceolate, apex acute to acuminate, ± erect in fruit, involute at tip; ovary obscurely to prominently crested with 3 or 6 processes. Allium tolmiei
105 Tepals elliptic-oblong, apex obtuse, not involute at tip, connivent over ovary in fruit; ovary crestless or obscurely crested. Allium scilloides
106 Ovary distinctly crested with 3 or 6 low processes; sand and gravel deposits, along Columbia River from Ferry County, ne Washington, to mouth of John Day River, nc Oregon. Allium robinsonii
106 Ovary obscurely crested with 3 low, rounded processes; rocky, clay slopes and talus, e Oregon, Idaho, to c California, n Nevada, nw Utah. Allium parvum

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

... more about "Allium"
versatile +  and dorsifixed +
cordate +  and linear +
Dale W. McNeal Jr. +  and T. D. Jacobsen +
Linnaeus +
whorled +, opposite +  and alternate +
dilated +
not petiolate +
straight +
falcate +, flat +, channeled +, terete +  and linear +
conspicuous +
1;several +
roughened +  and smooth +
Mostly Northern Hemisphere +
Latin, classical name for garlic +
connate-coroniform +  and dilated +
sessile +  and pedicellate +
unisexual +  and bisexual +
loculicidal +
membranaceous +  and leathery +
paired +, paniculate +  and racemose +
persistent +
gray +  and brown +
crested;3-lobed +
many;several +
spreading +  and erect +
membranous +
zygomorphic +  and actinomorphic +
Sp. Pl. +  and Gen. Pl. ed. +
1753 +  and 1754 +
persistent +
flattened +  and terete +
wind-distributed +
1 +  and many +
obovoid +
adnate +  and free +
epipetalous +
1 +  and several +
capitate +  and more or less 3-lobed +
Liliaceae +
persisting +
distinct +
petal-like +
sepaloid +  and petaloid +
narrower +
9 +, 8 +  and 7 +