Astragalus missouriensis var. humistratus
Astragalus sect. Argophylli
archuleta milkvetch, Missouri milkvetch
10–15(–20) cm.
(when present) obsolete, single, few, or several to many.
odd-pinnate, usually petiolate, rarely short-petiolate or subsessile;
leaflets (1 or)3–39(–43).
9–12-flowered.
subcapitate to loosely flowered, flowers erect, ascending, spreading, declined, or nodding, secund, and retrorsely imbricate.
calyx 7.8–10 mm, tube 6–10 mm, lobes 1.5–3 mm;
corolla lavender, purple, or almost white, wing tips often white;
banner (17–)19–20.5 mm.
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.
tubes cylindric or deeply campanulate.
ascending to descending, dorsiventrally compressed, lunately incurved, oblong-ellipsoid, (12–)17–20 × 6–9 mm, unilocular, apex obcompressed proximal to incurved beak, glabrous or sparsely strigulose.
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.
33–40.
11–70.
basifixed or malpighian.
distinct (except anomalous forms of A. missouriensis, A. tephrodes, and A. zionis).
Astragalus missouriensis var. humistratus
Astragalus sect. Argophylli
Variety humistratus is locally distributed in Archuleta, Hinsdale, and La Plata counties, Colorado, and adjacent Rio Arriba County, New Mexico. It is anomalous in its strongly caulescent but mat-forming habit, and the slightly or plainly connate stipules. R. C. Barneby (1964) suggested a hybrid origin between Astragalus missouriensis and A. humistratus.
Variety humistratus is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(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.)
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