Astragalus columbianus |
Astragalus sect. Argophylli |
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Columbia milkvetch, Columbian milk-vetch |
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Habit | Plants caulescent, (8–)15–45 cm, strigulose, hairs basifixed; from superficial or barely subterranean caudex. | Herbs perennial (sometimes flowering as annual), usually tuft- or mat-forming, acaulescent, subacaulescent, or caulescent; caudex usually superficial or aerial, sometimes subterranean. |
Stems | decumbent to ascending, diffuse, leafless basally, strigulose. |
(when present) obsolete, single, few, or several to many. |
Leaves | 3.5–5.5 cm; stipules 1–6 mm, membranous at proximal nodes, herbaceous with membranous margins at distal nodes; leaflets 5–13, blades oblong-elliptic, narrowly oblanceolate, or linear-oblong, 3–12 mm, apex obtuse or obtuse and apiculate, surfaces strigulose, sometimes glabrescent adaxially. |
odd-pinnate, usually petiolate, rarely short-petiolate or subsessile; leaflets (1 or)3–39(–43). |
Racemes | subcapitate, loosely 2–10-flowered, flowers ascending; axis to 1 cm in fruit; bracts 1–5 mm; bracteoles 0–2. |
subcapitate to loosely flowered, flowers erect, ascending, spreading, declined, or nodding, secund, and retrorsely imbricate. |
Peduncles | ascending, 1.2–2.5 cm. |
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Pedicels | 0.6–1.5 mm. |
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Flowers | (17–)18.1–19.5(–20) mm; calyx cylindric, (9.5–10–11.5(–13) mm, strigose, tube 7–8.2 mm, lobes narrowly lanceolate-subulate, 2.4–4.5 mm; corolla white or whitish, keel maculate; banner incurved through 35°; keel 13.1–13.6 mm. |
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Corollas | purple, pink-purple, magenta-purple, violet, bluish, lilac, scarlet, ochroleucous, greenish white, or white, banner barely recurved (A. phoenix) or recurved through 20–50° (90–100° in A. accumbens), keel apex obtuse. |
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Calyx | tubes cylindric or deeply campanulate. |
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Legumes | ascending (humistrate), green, incurved through 0.25–0.5+ spiral, narrowly oblong-ellipsoid or lanceoloid-ellipsoid, dorsiventrally compressed, 25–40 × 8.5–10.5 mm, unilocular, fleshy becoming subligneous, prominently cross-reticulate, glabrous. |
usually deciduous, usually sessile, rarely subsessile or substipitate, gynophore sometimes present, usually ascending (humistrate), less often spreading or pendulous, subglobose to ellipsoid, narrowly lanceoloid, ovoid or oblong-ellipsoid, or lanceoloid-ovoid, straight or usually incurved, usually compressed dorsiventrally, sometimes obcompressed, 3-sided, turgid, or inflated, unilocular, subunilocular, or bilocular. |
Seeds | 48–51. |
11–70. |
Hairs | basifixed or malpighian. |
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Stipules | distinct (except anomalous forms of A. missouriensis, A. tephrodes, and A. zionis). |
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Astragalus columbianus |
Astragalus sect. Argophylli |
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Phenology | Flowering Apr–Jun. | |
Habitat | Rocky slopes in sagebrush and bunchgrass communities, on basalt. | |
Elevation | 100–700 m. (300–2300 ft.) | |
Distribution |
WA
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w North America; n Mexico |
Discussion | Astragalus columbianus, a narrow endemic, is known from only a few kilometers along the Columbia River at Priest Rapids Reservoir in Benton and Yakima counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 44 (44 in the flora). Section Argophylli comprises ten subsections, widespread in western North America from southern British Columbia and Saskatchewan southward to northern Baja California, northern Sonora, and western Texas. The subsections are: subsect. Argophylli (A. Gray) M. E. Jones (Astragalus argophyllus, A. callithrix, A. columbianus, A. cyaneus, A. desereticus, A. eurylobus, A. henrimontanensis, A. iodopetalus, A. piutensis, A. shortianus, A. tephrodes, A. tidestromii, A. uncialis, A. zionis); subsect. Pseudargophylli Barneby (A. feensis, A. waterfallii); subsect. Neomexicani Barneby (A. neomexicanus); subsect. Newberryani M. E. Jones (A. eurekensis, A. loanus, A. musiniensis, A. newberryi, A. phoenix, A. welshii); subsect. Concordi S. L. Welsh (A. concordius); subsect. Coccinei M. E. Jones (A. coccineus); subsect. Eriocarpi (A. Gray) Barneby (A. anserinus, A. funereus, A. inflexus, A. leucolobus, A. nudisiliquus, A. purshii, A. subvestitus, A. utahensis); subsect. Parryani Barneby (A. parryi); subsect. Missourienses M. E. Jones (A. accumbens, A. amphioxys, A. castaneiformis, A. chamaeleuce, A. consobrinus, A. cymboides, A. laccoliticus, A. missouriensis, A. piscator); and subsect. Anisi Barneby (A. anisus). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Astragalus > sect. Argophylli | Fabaceae > subfam. Faboideae > Astragalus |
Sibling taxa | ||
Subordinate taxa | ||
Name authority | Barneby: Mem. New York Bot. Gard. 13: 649. (1964) | A. Gray: Proc. Amer. Acad. Arts 6: 209. (1864) |
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