Astragalus argophyllus var. martini
Rev. N.-Amer. Astragalus, 207. 1923.
Hairs basifixed. Stems 0–5 cm. Leaves 1.5–8.5 cm; leaflets 11–17(or 19), blades usually obovate-cuneate or elliptic-oblong, rarely elliptic-oblanceolate, 2–10 mm, apex usually obtuse, rarely acute. Flowers: calyx 10.2–14(–14.7) mm, tube 8.4–10.9 mm, lobes 1.6–3.3 mm; corolla tinged lilac or dull purple; banner 18–21.5(–22.5) mm; keel 15.9–18.5 mm. Legumes ovoid to broadly lanceoloid-ellipsoid or oblong-ellipsoid, (17–)20–32(–37) × 8–12(–13) mm, strigulose or villous, hairs appressed to loosely spreading and, sometimes, contorted, to 0.6–1.7 mm.
Phenology: Flowering Apr–Aug.
Habitat: Dry gravelly or sandy hillsides, stony ridges, mesas, and canyon benches, in sagebrush, mountain brush, aspen, and spruce-fir communities.
Elevation: 1700–3100 m.
Distribution
Ariz., Colo., Idaho, Nev., Utah, Wyo.
Discussion
Where vars. martini and argophyllus overlap geographically in southeastern Idaho and adjoining Wyoming and Utah, the former is an obligate xerophyte, whereas the latter is found exclusively in moist ground. Even when closely sympatric, they are ecologically isolated. In this area, habit preferences of these varieties deserves careful field study. Plants of var. martini from the desert ranges in Millard County, western Utah, have longer, ascending, and more or less contorted hairs; in that regard, they approach Astragalus callithrix.
Selected References
None.