Astragalus cusickii A.Gray var. cusickii
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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
"Union Co., in the western [properly eastern] part of Oregon, Wm. C. Cusick, comm, by G. O. Woolson."—Holotypus, Cusick 68 in 1877, GH! isotypi, K (dated 1878), P!
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Synonyms
Phaca cusickii (A.Gray) Rydb.
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Description
Variety Description - Stipules at base of the stems evidently connate, the sheath ruptured only in age, the median and upper ones usually united by a stipular line, only the uppermost free; calyx-tube 4.4-5.8 mm. long, 3-4 mm. in diameter, the disc 1-1.5 mm. deep; petals white or creamy-white, concolorous; banner rhombic-elliptic, mostly 14—15.5 mm. long; keel 9.7-11 mm. long; stipe of the pod 3-5 (6) mm. long, the body (2) 2.5-4.8 cm. long, the papery-membranous valves not mottled, turning stramineous when ripe; ovules 10-20.
Distribution and Ecology - Steep rocky and gravelly clay slopes and canyon terraces, sometimes hanging out from ledges or crevices of basalt cliffs, 1600-3000 feet, locally abundant and not uncommon along the Snake River and streams affluent from the west, from lower Sucker Creek, Malheur County, Oregon, downstream to the mouth of the Grande Ronde River, Asotin County, Washington.—Map No. 31.—May to July.
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Discussion
The typical variety of the Cusick milk-vetch is a handsome astragalus at all stages of growth, the mature plants forming large clumps of erect and ascending, sparely leafy (or at first sight apparently leafless) stems which bear aloft a mass of ochroleucous or almost clear white flowers; these are followed by the pendulous, transparent bladders of the fruit. At early anthesis some phases greatly resemble the more junceous forms of A. filipes, but such as are most likely to be confused with A. Cusickii may be distinguished by the pubescent ovary. Except for a small area along the lower Malheur River and Sucker Creek in Malheur County, Oregon, the two species occupy mutually exclusive ranges.
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Objects
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Distribution
Oregon United States of America North America| Washington United States of America North America|