Astragalus sophoroides

Plants clump- or tuft-forming, 2.5–20(–35) cm, densely strigose-strigulose, hairs malpighian; from shortly forked caudex; taproot tough, woody. Stems decumbent to ascending, densely strigose-strigulose, canes­cent. Leaves 3–8(–12) cm; stip­ules connate, 2–10 mm, scarious; leaflets 7–13, blades narrowly oblong or linear-elliptic, 3–12(–21) mm, apex subacute to obtuse, surfaces pubescent. Peduncles narrowly ascending, (0.7–)1–3(–4) cm, together with racemes slightly sur­passing leaves. Racemes 7–17-flowered; axis (0.7–)1–4 cm in fruit; bracts 1.5–5 mm; bracteoles 0. Pedicels 0.5–1 mm. Flowers 8.5–10 mm; calyx campanulate to turbinate-campanulate, 5–6.3 mm, densely white-strigulose, tube 3–3.6 mm, lobes lanceolate-subulate, 2–3 mm; corolla usually reddish lilac, rarely white tinged with pink, banner with pallid eye-spot; banner recurved through 45°; keel 5.7–6.8 mm. Legumes erect or ascending, stramineous, straight, oblong-ellipsoid, laterally com­pressed, 6.5–8 × 3–4 mm, thinly fleshy becoming papery, canescent-strigulose. Seeds 4–6.

Phenology: Flowering May–Jun.
Habitat: Sandy flats and knolls, on red sandstone and silts of the seleniferous Triassic Chinle Formation.
Elevation: 1200–1500 m.

Distribution

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Ariz.

Discussion

Astragalus sophoroides is restricted to eastern Coconino County. It is distinguished from the more wide­spread A. flavus var. higginsii by having slightly accres­cent calyces, marcescent petals, few ovules, and usu­ally relatively short peduncles, combined with typically reddish lilac flowers.

Selected References

None.

Lower Taxa

None.