Astragalus missouriensis var. amphibolus
Astragalus sect. Argophylli
Mancos milkvetch, Missouri milkvetch
to 10 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).
4–8-flowered.
subcapitate to loosely flowered, flowers erect, ascending, spreading, declined, or nodding, secund, and retrorsely imbricate.
calyx 8.5–13 mm, tube 7–10 mm, lobes 1.5–3 mm;
corolla usually pink-purple, rarely white;
banner (14.5–)16–22(–24) mm;
keel (11.5–)12.8–17.3(–18.5) 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.
sometimes deciduous, ascending to descending, dorsiventrally compressed, lunately incurved, ellipsoid, (11–)15–25 × 7–9 mm, unilocular, apex obcompressed proximal to incurved beak, strigose.
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.
35–55.
11–70.
basifixed or malpighian.
distinct (except anomalous forms of A. missouriensis, A. tephrodes, and A. zionis).
Astragalus missouriensis var. amphibolus
Astragalus sect. Argophylli
The fruits of var. amphibolus are initially dorsiventrally compressed, and ultimately dehisce apically while still attached to the inflorescence (though sometimes deciduous). The fruits have a lateral ridge down each valve, with the valves separated by more or less prominent bicarinate keels. In these features, along with the typically persistent fruits, the plants can be distinguished from the similar Astragalus amphioxys var. amphioxys where their ranges are contiguous, as in northwestern New Mexico and vicinity. R. C. Barneby (1947b, 1964) suggested that hybridization occurs between the two taxa.
(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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