Astragalus sparsiflorus
Proc. Amer. Acad. Arts 6: 205. 1864.
Plants annual or perennial (short-lived), 3.5–33 cm, sparsely strigulose; from superficial caudex; taproot slender. Stems prostrate or decumbent, sparsely strigulose. Leaves 1.5–10.5 cm; stipules distinct, 1–4 mm, mostly herbaceous or submembranous; leaflets 9–19, blades obovate, oblong-oblanceolate to -obovate, obcordate, suborbiculate, or elliptic, 2–15 mm, apex obtuse or emarginate, surfaces sparsely strigulose abaxially, glabrous adaxially. Peduncles ascending, 1–7.5 cm. Racemes (1 or)2–10-flowered, flowers ascending or spreading; axis (0–)1–4 cm in fruit; bracts 1–2.5 mm; bracteoles 2. Pedicels 1–3.5 mm. Flowers 5.5–8 mm; calyx campanulate, 3–4.3 mm, strigulose, hair white or partly black, tube 1.5–2.8 mm, lobes subulate, 1.2–2 mm; corolla white, banner with pink veins; banner recurved through 45–90°; keel 3.6–5 mm, apex bluntly deltate. Legumes ascending, spreading, or loosely declined, green, purplish, or purple- or red-mottled becoming brownish or stramineous, incurved, narrowly oblanceoloid or obliquely semi-ovoid, ± inflated, ± 3-sided compressed, (5–)6–26 × 2.7–5 mm, thin becoming papery, finely strigulose, hairs straight, appressed; gynophore conical, short. Seeds 6–15.
Distribution
Colorado.
Discussion
Varieties 2 (2 in the flora).
The two abruptly different varieties of Astragalus sparsiflorus sometimes occur in close proximity without apparent intergradation and may deserve specific rank (R. C. Barneby 1964).
Selected References
None.
Key
| 1 | Leaves 1.5–5 cm, leaflet blades broadly elliptic, obovate, or suborbiculate, 2–7 mm; calyces 3–3.5 mm, tubes 1.5–1.9 × 1.6–2 mm, lobes 1.5–2 mm; banners 5.5–6.6 mm; legumes (5–)6–8 × 2.7–4 mm; seeds 6–8. | Astragalus sparsiflorus var. sparsiflorus |
| 1 | Leaves 2.5–10.5 cm, leaflet blades mostly oblong-oblanceolate or -obovate, 4–15 mm; calyces 3.2–4.3 mm, tubes 2–2.8 × 2–2.4 mm, lobes 1.2–1.7 mm; banners 6.2–8 mm; legumes 11–26 × 3–5 mm; seeds 10–15. | Astragalus sparsiflorus var. majusculus |