Astragalus terminalis
Proc. Amer. Acad. Arts 17: 370. 1882.
Plants loosely tuft- or mat-forming, 20–40 cm, strigulose, hairs malpighian; from superficial caudex. Stems erect, decumbent, or incurved-ascending, with 2–4 much-elongated internodes, strigulose. Leaves (3–)5–17 cm; stipules 4–7 mm, papery-scarious at proximal nodes, submembranous at distal nodes; leaflets (11 or)13–21, blades oblong-obovate, ovate, linear-oblong, or linear-elliptic, 3–17 mm, apex truncate to deeply retuse or obtuse to subacute, surfaces strigulose. Peduncles incurved-ascending, 6–20(–24) cm. Racemes 7–25(–30)-flowered, flowers nodding; axis 1.5–12(–16) cm in fruit; bracts 1–2.5 mm; bracteoles 0–2. Pedicels 0.7–5 mm. Flowers (11.2–)12.5–16.6 mm; calyx campanulate, 4.5–7 mm, strigulose, tube 3.8–5.5 mm, lobes subulate, 0.7–1.2(–1.5) mm; corolla white, keel tip maculate; banner recurved through 90°; keel 8.8–10.7 mm. Legumes erect, stramineous, ± straight or slightly incurved, narrowly oblong or ovoid-oblong, obcompressed, 12–17 × 3.3–6.3 mm, ± bilocular, fleshy becoming leathery, glabrous; septum 0.7–1.1 mm wide; sessile. Seeds 24–36.
Phenology: Flowering Jun–Aug.
Habitat: Sagebrush or coniferous forest communities, rocky substrates.
Elevation: 1600–3200 m.
Distribution
Idaho, Mont., Wyo.
Discussion
Astragalus terminalis ranges from southwestern Montana into the adjacent mountains of eastern Idaho and Teton County, Wyoming.
Astragalus terminalis is commonly called the railhead milkvetch because its type was collected from the then terminus of the Utah and Northern Railroad. It has the typical erect fruits and distinct stipules of A. reventus and allies but differs in its malpighian hairs.
Selected References
None.