Astragalus ensiformis
Plants 8–45 cm, strigulose; from shallow, subterranean caudex. Stems several, decumbent or sprawling to erect, (1–)2–6(–8) cm underground, strigulose. Leaves 4–16 cm; stipules strongly decurrent, 3–11 mm, papery at proximal nodes, subherbaceous at distal nodes; leaflets (5–)11–23, blades ovate to oblong, obovate, or oblanceolate, 6–24 mm, apex obtuse to retuse, surfaces strigose to sparsely so abaxially, strigose or glabrous adaxially. Peduncles incurved-ascending, subhorizontal in fruit, 2.5–13(–24) cm. Racemes 10–30-flowered, flowers ascending to declined; axis 3–14 cm in fruit; bracts 2–6 mm; bracteoles 0–2. Pedicels 1–3.5 mm. Flowers (11–)13–17 mm; calyx short-cylindric, 5.2–7.8 mm, black-pilosulous, tube 4.5–6.5 mm, lobes subulate, 1.2–2.5 mm; corolla purplish to pink-purple, wing tips pale to white; keel 10.5–10.8 mm. Legumes firmly attached to receptacle, falling while still attached to pedicel, ascending to descending (sometimes humistrate), green and red-tinged becoming brownish, incurved 0.5 spiral, narrowly oblong, subterete, laterally compressed when pressed, sides convex, elliptic in cross section, dorsal suture forming a prominent ridge, 15–32 × 4–7(–8) mm, bilocular, thick becoming leathery, strigose to strigulose; stipe 0.5–2 mm. Seeds 24–36.
Phenology: Flowering Apr–May.
Habitat: Pinyon-juniper, sagebrush, salt desert shrub, and blackbrush communities on various substrates.
Elevation: 1200–2400 m.
Distribution
Ariz., Nev., Utah.
Discussion
Astragalus ensiformis is known from Mohave County in Arizona, Lincoln County in Nevada, and Washington County in Utah.
Astragalus ensiformis is distinguishable from A. minthorniae by its superficial root crown, closely clustered, conspicuous, basal stipules, and legumes that are ± straight.
Selected References
None.