Astragalus coltonii var. moabensis M.E.Jones
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
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Family
Fabaceae
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Scientific Name
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Type
"Collected at Moab by Miss Eastwood and by myself at Green River, Utah."—No specimen with correct data found at CAS or POM, the only Eastwood material being her No. 9 in 1892, from Monticello, San Juan County, here selected as neotypus. The paratypus from
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Synonyms
Homalobus canovirens Rydb., Astragalus canovirens (Rydb.) Barneby
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Description
Variety Description - Commonly more robust and more leafy than var. Coltoni, the stems arising always from a buried, knotty, or shortly forking root-crown, the stems and herbage strigulose with hairs up to (0.4) 0.5-0.8 mm. long, cinereous, greenish- cinereous or canescent, the leaflets often bicolored, brighter green and usually less densely pubescent above than beneath; leaves (2) 3-9 cm. long, shortly petioled or the upper ones subsessile, with (5) 9-17 (19) oblong, cuneate-oblong, or a few ovate and flat, or in some upper leaves linear-oblong or -oblanceolate and involute, obtuse, truncate, or retuse leaflets (3) 5-20 mm. long, the terminal one nearly always jointed like the rest, the joint obscure (lacking) only in a few upper leaves; peduncles (4) 6.5-21 cm. long; racemes (6) 10-30-flowered; stipe of the pod 5-11 mm. long, the body 1.9-3.5 cm. long, (3) 3.5-6 mm. in diameter.
Distribution and Ecology - Dry hills, mesas and canyon terraces, commonly in juniper-piñon woodland, often associated with sagebrush, in sandy or gravelly soils derived from sandstone or in the valleys in rich alluvial clays, 4800-7000 (7500) feet, locally abundant in the foothills and on the lower slopes of the La Sal and Abajo Mountains in southeastern Utah and adjoining Colorado, extending more rarely south across the San Juan River to extreme northwestern New Mexico and northeastern Arizona; in the Moab region intergradient to var. Coltoni.—Map No. 25.—April to June.
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Discussion
The Moab milk-vetch is distinguished from var. Coltoni, with exceptions briefly mentioned in the introductory paragraphs, by its coarser, more leafy stems which rise farther from the ground before producing the first peduncle. And it seems to be adapted to less xerophytic microhabitats. The Four Corners country offers extensive areas of badlands and desertic talus where var. Coltoni might be expected to find a congenial home, but these situations are shunned by var. moabensis in favor of brushy slopes and sagebrush flats where the soil is richer and better watered.
An ambiguous specimen, apparently referable to var. moabensis but possibly deserving more attention, was collected ostensibly at Robertson, Uinta County, Wyoming, in June 1932, by R. C. Rollins (No. 177, RM, distributed as Hedysarum sp.). If correctly identified as A. Coltoni, it was probably mislabeled.
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Objects
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Distribution
Utah United States of America North America| Colorado United States of America North America| New Mexico United States of America North America| Arizona United States of America North America|