Astragalus straturensis
Plants slender, forming bushy clumps, 13–36(–48) cm, strigulose; from superficial or shallow, subterranean caudex. Stems decumbent to ascending or erect, strigulose. Leaves 3.5–10 cm; stipules 1–2.5 mm, thinly herbaceous becoming papery; leaflets (3–)9–19, blades oblong to linear or oval, 3–13 mm, apex obtuse to retuse, surfaces strigose abaxially, glabrous adaxially. Peduncles ascending, 1.5–7.5 cm. Racemes 9–25-flowered, flowers ascending to declined; axis 1.5–14(–17) cm in fruit; bracts 0.8–1.5 mm; bracteoles 0. Pedicels 0.8–1.5 mm. Flowers 6.5–8.5 mm; calyx 3.5–4.2 mm, strigose, tube 2.5–3.5 mm, lobes triangular, 0.7–1.1 mm; corolla pink-purple with white wing tips; banner recurved through 50–90°; keel 5–6 mm. Legumes pendulous, stramineous, incurved or straight, oblong, 3-sided compressed, 10–15(–17) × 2.2–3 mm, thinly fleshy becoming papery, strigose; septum 0.8–1 mm wide; stipe 1.4–2.5 mm. Seeds 10–13. 2n = 22.
Phenology: Flowering late Apr–Jun.
Habitat: Sagebrush, pinyon-juniper, ponderosa pine, and mountain brush communities.
Elevation: 1500–2500 m.
Distribution
Ariz., Nev., Utah.
Discussion
Astragalus straturensis is known from Mt. Trumbull, Mohave County in Arizona, Needle Mountains and Highland Range, Lincoln County in Nevada, and Beaver, Iron, Millard, and Washington counties in Utah.
The relationships of Astragalus straturensis lie with species in sect. Miselli with distributions southward into the Sierra Madre Occidental, Mexico. It is the only Astragalus in its region that is perennial, with pendulous, stipitate, dorsally-grooved fruits, and purple flowers.
Selected References
None.