Astragalus didymocarpus

Plants (1.5–)3–35(–45) cm, sparsely strigose; taproot slen­der. Stems erect, ascending, dif­fuse, or prostrate, sparsely stri­gose. Leaves (0.8–)1–7.5 cm; stipules (0.5–)1–5 mm, thinly herbaceous becoming papery-membranous; leaflets (7 or)9–17, blades linear-oblanceolate, -elliptic, oblanceolate, oblong-cuneate, or cuneate, 1.5–14 mm, apex deeply retuse, surfaces strigose abaxially, strigose, glabrate, or glabrous adaxially. Peduncles erect or incurved-ascending, (0.5–)1–8 cm. Racemes (5–)7–30-flowered, flowers erect or ascending, straight; axis 0.2–2(–2.2) cm in fruit, not elongating; bracts 0.6–3 mm; bracteoles 0. Pedicels 0.1–0.5(–0.6) mm. Flowers 2.8–10 mm; calyx 2.5–5.7 mm, pilosulous or villosulous, tube 1.5–3.8 mm, lobes subulate to subulate-setaceous, 0.8–2.5 mm; corolla whitish and tinged lavender, or pink-purple with white or pale wing tips; keel 2.4–7.2 mm. Legumes erect or spreading, green or purple-tinged becoming brownish, straight, plumply ovoid or sub­globose, somewhat laterally compressed, (2–)2.3–4 × 1.5–3 mm, thinly fleshy becoming stiffly papery, coarsely reticulate or ridged, strigulose, strigulose-hirsutulous, pilosulous, or glabrous; gynophore slender, 0–0.5 mm.

Distribution

sw United States, nw Mexico.

Discussion

Varieties 4 (4 in the flora).

Astragalus didymocarpus has erect flowers and fruits, which contrast with the late anthesis nodding flowers and declined fruits of A. gambelianus.

Selected References

None.

Lower Taxa

Astragalus didymocarpus var. didymocarpus, Astragalus didymocarpus var. dispermus, Astragalus didymocarpus var. milesianus, Astragalus didymocarpus var. obispensis

Key

1	Keel petals 2.4–4.5 mm.	> 2
2	Calyces: hairs mostly black, lobes 0.8–1.4(–2) mm, tubes 1.5–2.8 mm; stems usually erect or ascending, rarely diffuse; Sacramento and San Joaquin valleys s from Contra Costa County and s Coast Ranges, foothills of s California and Channel Islands to Baja California, e Inyo County and adjacent Nevada.	Astragalus didymocarpus var. didymocarpus
2	Calyces: hairs mostly white, lobes (1.3–)1.6–2.4 mm, tubes 1.7–2.3 mm; stems diffuse, weakly ascending, or prostrate; s Mojave and Colorado deserts, California and Nevada, to c, s Arizona and Mexico.	Astragalus didymocarpus var. dispermus
1	Keel petals (4.7–)5.3–7.2 mm.	> 3
3	Keel petals abruptly incurved, apex broadly rounded; coastal San Luis Obispo and Santa Barbara counties.	Astragalus didymocarpus var. milesianus
3	Keel petals incurved, apex narrowly triangular, acute or subacute, slightly beaklike; interior s California, Los Angeles County to Baja California.	Astragalus didymocarpus var. obispensis