Astragalus amphioxys var. modestus |
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crescent milkvetch, modest milkvetch |
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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 |
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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 |
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 |
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 | |
Sibling taxa | |
Name authority | Barneby: Leafl. W. Bot. 9: 89. (1960) |
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