Astragalus oocarpus

Plants perennial, stout, 60–130 cm, glabrate to strigulose; from superficial caudex. Stems stiffly erect or ascending, or finally straggling and supported on bushes, fistulose, glabrous. Leaves (4.5–)6–17 cm; stipules distinct, 2–14 mm, herbaceous becoming papery; leaflets (17 or)19–35, blades broadly lanceolate to oblong-ovate or oblong-obovate, 6–33 mm, apex retuse or truncate-obtuse, surfaces mostly glabrous, margins and midribs sparsely strigulose. Peduncles erect or incurved-ascending, 1.5–6(–7) cm. Racemes (15–)20–60(–75)-flowered, flowers ascending; axis (3–)4–19 cm in fruit; bracts 1.2–3 mm; bracteoles 0–2. Pedicels 1–3.5 mm. Flowers 10.5–12.5 mm; calyx campanulate, 4.5–6 mm, sparsely strigulose, tube 3.5–4.6 mm, lobes deltate or subulate, 0.8–1.8 mm; corolla ochroleucous, rarely tinged purplish, drying brownish; banner abruptly recurved through 70–90°; keel 9–10.8 mm, apex sharply triangular. Legumes persistent on receptacle, erect, stramineous, straight, obliquely ovoid-acuminate, greatly inflated, scarcely bladdery, terete or somewhat dorsiventrally compressed, 15–25 × (8.5–)10–16 mm, fleshy becoming stiffly papery, glabrous or minutely strigulose. Seeds 44–58. 2n = 22.

Phenology: Flowering May–Aug.
Habitat: Openings in chaparral, gravelly flats and slopes in thin oak woodlands.
Elevation: (400–)800–1600 m.

Calif.

Discussion

Astragalus oocarpus is known primarily in the mountains of interior San Diego County. It differs from A. douglasii mainly by a thickening and coarsening of all its tissues, especially the petals, which are fleshy and turn brown upon drying (unless dried quickly). D. Isely (1998) provided a key by flower, by fruit, and by geography, to the four similar and related taxa of Astragalus in San Diego County (A. deanei, A. douglasii vars. parishii and perstrictus, and A. oocarpus).

Selected References

None.

Lower Taxa