The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links
Photo is of parent taxon

crescent milkvetch, modest milkvetch

Flowers

calyx cylindro-campanulate, tube 6.1–9.3 mm, lobes 1.1–2.6 mm;

corolla banner 12.8–16 mm;

keel 11–12.7 mm.

Legumes

16–40 mm, crescentic or incurved through 1/2 their length.

Seeds

44–58.

Astragalus amphioxys var. modestus

Phenology Flowering Mar–May.
Habitat Dry gravelly hillsides, in blackbrush, four-wing saltbush, Indian ricegrass, needle-and-thread grass, old man sagebrush, mixed grass communities, on sandy silt, limestone, or cindery volcanic debris.
Elevation 1100–1500 m. (3600–4900 ft.)
Distribution
from FNA
AZ; NV; UT; Dry gravelly hillsides; in blackbrush; four-wing saltbush; Indian ricegrass; needle-and-thread grass; old man sagebrush; mixed grass communities; on sandy silt; limestone; or cindery volcanic debris
[BONAP county map]
Discussion

The small-flowered var. modestus forms the other major extreme in flower size within the species, contrasting with the large-flowered var. vespertinus. It is local, forming uniform colonies within the range of var. amphioxys but only from valleys affluent to the Colorado River from San Juan and eastern Kane counties, Utah, and northern Mohave County, Arizona, with disjunct populations in Lincoln County, Nevada. Some plants from northeastern Arizona and northwestern New Mexico have similarly small flowers and might represent an eastward extension of var. modestus; however, in this case introgression from Astragalus missouriensis cannot be ruled out.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Astragalus > sect. Argophylli > Astragalus amphioxys
Sibling taxa
A. amphioxys var. amphioxys, A. amphioxys var. musimonum, A. amphioxys var. vespertinus
Name authority Barneby: Leafl. W. Bot. 9: 89. (1960)
Web links