Astragalus titanophilus

Plants slender, wiry, 15–30 cm, gray-strigulose, hairs sometimes flattened and scalelike; from shallow, subterranean caudex. Stems prostrate to ascending, 1–7 cm underground, gray-strigulose. Leaves 2.5–9 cm; stipules distinct, 2–8 mm, papery at proximal nodes, firm at distal nodes; leaflets 7–15, jointed to rachis throughout, blades narrowly linear to linear-oblong, 2–12(–16) mm, apex obtuse to emarginate, surfaces strigulose. Peduncles ascending or divaricate and incurved, 3.5–9.5 cm, surpassing leaves. Racemes (3–)7–20-flowered, flowers spreading or ± decurved; axis 2–14 cm in fruit; flowers declined or nodding; bracts 0.8–2 mm; bracteoles usually 0. Pedicels 2–6 mm. Flowers 7.3–8.5 mm; calyx campanulate, 4–5.9 mm, strigose, tube 3.2–4.5 mm, lobes subulate or triangular-subulate, 0.5–1.4 mm; corolla ochroleucous, tinged or veined with lilac, or pinkish white; banner strongly recurved through 100–130°; keel 7–8 mm, apex bluntly triangular. Legumes declined or pendulous, green or purplish becoming brown-stramineous, straight or gently incurved or decurved, narrowly oblong to ellipsoid, strongly laterally compressed, (18–)22–35 × 3.2–4.6(–5) mm, stiffly papery, strigulose; subsessile, base contracted into stout, stipelike neck 1–1.5 mm. Seeds (16–)20–24.

Phenology: Flowering Apr–Jul.
Habitat: Sandy, gravelly, or fine-textured substrates in pinyon-juniper communities.
Elevation: 1300–1900 m.

Ariz.

Discussion

Astragalus titanophilus is known only from Coconino and Mohave counties.

Astragalus titanophilus was initially placed at the varietal level within A. convallarius, where it could still reside without serious damage to the taxonomy. Present placement of A. titanophilus and A. xiphoides within sect. Lonchocarpi is problematic and additional investigation is suggested.

Selected References

None.

Lower Taxa