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three-corner leek, three-cornered leek, white flower onion

Howell's onion

Bulbs

5–20+, not clustered on stout primary rhizome, rhizomes absent, increase bulbs absent or ± equaling parent bulbs, never appearing as basal cluster, ovoid, 1–2 × 1–2 cm;

outer coats enclosing renewal bulbs, ± translucent, yellow-brown, obscurely cellular-reticulate, thin, membranous, meshes delicate, cells vertically elongate, contorted, without fibers;

inner coats white, cells obscure, quadrate, or not visible.

usually solitary, not clustered on stout, primary rhizome, ovoid to ± globose, 0.9–1.7 × 0.8–2 cm;

outer coats enclosing bulb, dark reddish brown, membranous, lacking cellular reticulation or cells arranged in only 2–3 rows distal to roots, ± quadrate, without fibers;

inner coats light brown to 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, ± carinate, 15–50 cm × 3–15 mm, margins entire.

persistent, withering from tip by anthesis, 1, basally sheathing, sheath not extending much above soil surface;

blade solid, terete, 20–55 cm × 1–4 mm.

Scape

persistent, clustered, 1–4, erect, solid, sharply 3-angled, 10–40 cm × 1–10 mm.

persistent, solitary, erect, solid, terete, 15–60 cm × 1–3.5 mm.

Umbel

persistent, lax, loose, 3–15-flowered, ± 1-sided, bulbils unknown;

spathe bracts persistent, 1–2, 3-veined, narrowly lanceolate, ± equal, apex acute.

persistent, erect, compact, 15–100-flowered, hemispheric, bulbils unknown;

spathe bracts persistent, 2–4, 5–8-veined, lanceolate to broadly ovate, ± equal, apex mucronate to acuminate or long-acuminate.

Flowers

becoming pendent, campanulate, 10–18 mm;

tepals erect to spreading, white with prominent green midrib, lanceolate, ± equal, becoming membranous in fruit, margins entire, apex acute;

stamens included;

anthers yellow;

pollen yellow;

ovary crestless;

style linear, ± equaling stamens;

stigma capitate, scarcely thickened, unlobed;

pedicel 15–25 mm.

stellate to ± campanulate, 5–8 mm;

tepals spreading to ± erect, white to pink or pale lavender with darker midveins, ovate to oblong, ± equal, becoming papery in fruit, margins entire, apex obtuse;

stamens ± equaling tepals to long-exserted;

anthers yellow or purple;

pollen yellow;

ovary crested;

processes 6, prominent, ± triangular, margins ± irregularly denticulate to laciniate;

style linear, equaling stamens or longer;

stigma capitate, 3-lobed, lobes slender, recurved;

pedicel 6–25 mm.

Seed(s)

coat dull;

cells minutely roughened.

coat dull or shining;

cells minutely roughened.

2n

= 18.

Allium triquetrum

Allium howellii

Phenology Flowering Mar–Apr.
Habitat Disturbed sites
Elevation 0–100 m (0–300 ft)
Distribution
from FNA
CA; sw Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Allium triquetrum is a garden escape, introduced from southwestern Europe, and is potentially a noxious weed.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 3 (3 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Scape 15–25(–35) cm; umbels generally 15–30 (–50)-flowered; tepals usually white to pink or lavender; ovary crests purple in fresh specimens.
var. howellii
1. Scape 20–60 cm; umbels generally 25–100-flowered; tepals usually white or pale pink; ovary crests white or greenish in fresh specimens.
→ 2
2. Stamens exserted, 2–4 mm.
var. sanbenitense
2. Stamens ± equaling tepals.
var. clokeyi
Source FNA vol. 26, p. 257. FNA vol. 26, p. 250.
Parent taxa Liliaceae > Allium Liliaceae > Allium
Sibling taxa
A. aaseae, A. abramsii, A. acuminatum, A. ampeloprasum, A. amplectens, A. anceps, A. atrorubens, A. bigelovii, A. bisceptrum, A. bolanderi, A. brandegeei, A. brevistylum, A. burlewii, A. campanulatum, A. canadense, A. cepa, A. cernuum, A. columbianum, A. constrictum, A. coryi, A. cratericola, A. crenulatum, A. crispum, A. cuthbertii, A. denticulatum, A. diabolense, A. dichlamydeum, A. dictuon, A. douglasii, A. drummondii, A. elmendorfii, A. falcifolium, A. fibrillum, A. fimbriatum, A. fistulosum, A. geyeri, A. gooddingii, A. haematochiton, A. hickmanii, A. hoffmanii, A. howellii, A. hyalinum, A. jepsonii, A. kunthii, A. lacunosum, A. lemmonii, A. macropetalum, A. macrum, A. madidum, A. membranaceum, A. monticola, A. munzii, A. neapolitanum, A. nevadense, A. nevii, A. nigrum, A. obtusum, A. oleraceum, A. paniculatum, A. parishii, A. parryi, A. parvum, A. passeyi, A. peninsulare, A. perdulce, A. platycaule, A. plummerae, A. praecox, A. punctum, A. rhizomatum, A. robinsonii, A. rotundum, A. runyonii, A. sanbornii, A. sativum, A. schoenoprasum, A. scilloides, A. serra, A. sharsmithiae, A. shevockii, A. simillimum, A. siskiyouense, A. speculae, A. stellatum, A. textile, A. tolmiei, A. tribracteatum, A. tricoccum, A. tuberosum, A. tuolumnense, A. unifolium, A. validum, A. victorialis, A. vineale, A. yosemitense
A. aaseae, A. abramsii, A. acuminatum, A. ampeloprasum, A. amplectens, A. anceps, A. atrorubens, A. bigelovii, A. bisceptrum, A. bolanderi, A. brandegeei, A. brevistylum, A. burlewii, A. campanulatum, A. canadense, A. cepa, A. cernuum, A. columbianum, A. constrictum, A. coryi, A. cratericola, A. crenulatum, A. crispum, A. cuthbertii, A. denticulatum, A. diabolense, A. dichlamydeum, A. dictuon, A. douglasii, A. drummondii, A. elmendorfii, A. falcifolium, A. fibrillum, A. fimbriatum, A. fistulosum, A. geyeri, A. gooddingii, A. haematochiton, A. hickmanii, A. hoffmanii, A. hyalinum, A. jepsonii, A. kunthii, A. lacunosum, A. lemmonii, A. macropetalum, A. macrum, A. madidum, A. membranaceum, A. monticola, A. munzii, A. neapolitanum, A. nevadense, A. nevii, A. nigrum, A. obtusum, A. oleraceum, A. paniculatum, A. parishii, A. parryi, A. parvum, A. passeyi, A. peninsulare, A. perdulce, A. platycaule, A. plummerae, A. praecox, A. punctum, A. rhizomatum, A. robinsonii, A. rotundum, A. runyonii, A. sanbornii, A. sativum, A. schoenoprasum, A. scilloides, A. serra, A. sharsmithiae, A. shevockii, A. simillimum, A. siskiyouense, A. speculae, A. stellatum, A. textile, A. tolmiei, A. tribracteatum, A. tricoccum, A. triquetrum, A. tuberosum, A. tuolumnense, A. unifolium, A. validum, A. victorialis, A. vineale, A. yosemitense
Subordinate taxa
A. howellii var. clokeyi, A. howellii var. howellii, A. howellii var. sanbenitense
Name authority Linnaeus: Sp. Pl. 1: 300. (1753) Eastwood: Leafl. W. Bot. 2: 109. (1938)
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