Plants slender, 10–60 cm, strigulose-villosulous; from shallow to deep subterranean caudex, branches rhizomatous. Stems (2–)3.5–40 cm under­ground, strigulose-villosulous. Leaves (1–)1.5–5.5 cm; stipules connate-sheathing and papery-membranous at proximal nodes, distinct and subherbaceous at distal nodes, 1.5–5(–6.5) mm; leaflets 9–17, blades oblong-obovate to oblanceolate or orbiculate, 2–8(–10) mm, apex obtuse to retuse, surfaces strigulose-villosulous. Peduncles weakly ascending becoming declined, (1–)1.5–5(–6.5) cm. Racemes 4–14-flowered, flowers ascending; axis 0.5–2.5 cm in fruit; bracts 1.3–2.7 mm; bracteoles usu­ally 2. Pedicels 0.8–1.4 mm. Flowers (8.5–)9–11 mm; calyx campanulate, 4–6.3 mm, strigulose-villosulous, tube 3–4 mm, lobes subulate, 1–2.5 mm; corolla flesh-pink; banner recurved through 50°; keel 7–8.9 mm. Legumes deflexed, green or purplish becoming brownish, straight or slightly decurved, cylindroid-ellipsoid, obscurely and obtusely 3-sided compressed, 9–17 × 4–6 mm, stiffly papery, strigulose; subsessile. Seeds (10–)14–18. 2n = 22, 44.

Phenology: Flowering Apr–Jun.
Habitat: Sandy and gravelly soils on granite, sandstone, and limestone, with juniper, scrub-oak, and arid grasslands.
Elevation: 1400–2200 m.

Distribution

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N.Mex., Tex.

Discussion

The pale flowers and grayish foliage of Astragalus pictiformis make it inconspicuous in the arid grasslands and grayish soil of central and south-central New Mexico and western trans-Pecos Texas, where it is rather frequent. The species is reported to be tetraploid (x = 22) (R. Spellenberg 1976), a condition that appar­ently is rare in New World astragali. Two of the three known Astragalus tetraploids in the New World are rhizomatous (A. pictiformis and the unrelated A. layneae), a condition that is often associated with polyploidy in other plant groups (G. L. Stebbins 1971).

Selected References

None.

Lower Taxa

None.