Plants loosely tuft-forming, 5–20(–30) cm, strigulose; from branched, subterranean caudex, underground for 6+ cm, and stout taproot. Stems sprawling, slender and delicate, forming entangled clumps, strigulose, green. Leaves 2.5–10 cm; stip­ules connate-sheathing at proxi­mal nodes, distinct at distal nodes, 2–5 mm, thinly herbaceous or submembranous; leaflets (9–)15–23(–27), blades narrowly elliptic, lanceolate, or ovate, 3–15 mm, apex subacute or obtuse, surfaces sparsely strigulose abaxially, glabrate adaxially. Peduncles ascending, 2–2.5 cm, shorter than leaves. Racemes loosely (1 or)2 or 3(–5)-flowered; axis 0.2–1 cm in fruit; bracts 1.3–3.3 mm; bracteoles 0–2. Pedicels 1.2–2.1 mm, 1.4–2.5 mm in fruit. Flowers 8.5–11.8 mm; calyx campanu­late to subcylindric, 4–5.7 mm, densely to sparsely stri­gulose, tube 2.7–3.4 mm, lobes subulate or lanceolate-subulate, 1.1–2.5 mm; corollas white, keel apex mac­ulate with dull bluish purple; banner recurved through 45°; keel 6–7.5 mm. Legumes stramineous, slightly decurved, oblong- or lanceoloid-ellipsoid, obcompressed and bluntly 3-sided, faces low-convex, 8–14 × 2.5–4 mm, papery, translucent, sparsely strigulose, hairs 1.8–2.1 mm, unilocular; stipe 0–1.5 mm. Seeds 6–10.

Phenology: Flowering Jun–Aug.
Habitat: Moist sedge meadows and stream margins.
Elevation: 800–2700 m.

Distribution

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Colo., Idaho, Mont., Wyo.

Discussion

Astragalus leptaleus is a delicate species easily over­looked in floriferous meadows, which are often held privately and heavily utilized for livestock. These fac­tors combine to suggest that it may be more common than records in collections would suggest.

Selected References

None.

Lower Taxa

None.