Astragalus nuttallianus var. austrinus
Astragalus nuttallianus var. macilentus
rio fronteras milkvetch, smallflower milkvetch, southern small flower milk vetch
small milkvetch, turkeypeas
(1–)3–25(–35) cm.
8–30(–38) cm.
1–6.5 cm;
leaflets 7–11(–17), blades often narrowly elliptic, sometimes broader proximally, apex rounded.
(1.5–)2–9.5 cm;
leaflets 7–23, blades sometimes dimorphic, distal ones more narrow, linear-elliptic, oblong-oblanceolate, broadly elliptic, or obovate, apex acute or truncate-emarginate.
(1–)2–5(–8)-flowered;
axis very short in fruit.
(2 or)3–27-flowered;
axis to (0.5–)1–3 cm in fruit.
3–10 cm.
2.5–9 cm.
calyx 3.7–5.4 mm, silvery-pilose, tube (1.5–)2–3 mm, lobes 1.8–2.1 mm;
corolla white or tipped pink or purple, banner (4–)5.5–7 mm;
keel apex triangular-acute or sharply deltate, usually beaklike.
calyx 3.4–5.6 mm, loosely sparsely strigulose-pilosulous, tube 2–3.1 mm, lobes 1.1–3 mm;
corolla banner (6.4–)8.5–13 mm;
keel apex obtusely rounded.
13–24 × 1.8–2.8(–3) mm, glabrous or strigulose.
(10–)13–25 × 1.8–2.7 mm, glabrous;
substipitate.
14–18.
12–22.
= 24.
Astragalus nuttallianus var. austrinus
Astragalus nuttallianus var. macilentus
Variety austrinus occurs from southern Kansas to the southern tip of Texas and northern Mexico, and westward to Arizona and southern California, where it grades into var. imperfectus (D. Isely 1998).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Variety macilentus occurs from south-central Texas to the western tip of the state. Species level recognition may be justified because of its elongating inflorescences, substipitate fruits, obtuse keels, and absence of intergradation with sympatric Astragalus nuttallianus (D. Isely 1998). It is easily confused with A. emoryanus in flower, which is distinguished by its sessile and deciduous fruits.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
KS Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
