Astragalus bisulcatus var. haydenianus (A.Gray) Barneby
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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
"South-western Colorado, between Parrott City and the Mancos, 8000 feet."—Holotypus, Brandegee 1285, collected (at "7000 ft.") in the summer of 1875, GH! isotypi, K, US!
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Synonyms
Astragalus haydenianus A.Gray, Tragacantha haydeniana (A.Gray) Kuntze, , Diholcos haydenianus (A.Gray) Rydb., Astragalus grallator S.Watson, Homalobus grallator (S.Watson) Rydb.
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Description
Variety Description - Usually robust, the stems commonly decumbent and radiating, sometimes erect and ascending in clumps, (1.5) 3-5 (7) dm. long; leaflets (13) 21-35, 0.5—2.7 cm. long; racemes mostly 35—80-flowered, becoming narrowly cylindrical, the fruiting axis (4) 5.5-25 cm. long; bracts (2.5) 3-5 mm. long; calyx-tube pallid, 3.1-4 mm. long, 2.3-2.7 mm. in diameter, the subulate teeth 1-2.7 mm. long; petals white or whitish; banner 8-11 mm. long, (3) 3.3-5 mm. wide; wings 7.1-10.2 mm. long, the claws 3.3-4.7 mm., the blades (4.6) 5-6.7 mm. long, 1.4—2.1 mm. wide; keel 6.7—9.6 mm. long, 0.5—2.5 mm. shorter than the banner, the claws 3—4.2 mm., the blades (3.8) 4.3—6 mm. long, (2) 2.2—2.6 mm. wide; anthers 0.45—0.6 mm. long; stipe of the pod 1.4—3 mm. long, the body ellipsoid or oblong-ellipsoid, (5) 6.5—9.5 mm. long, 2-4 mm. in diameter, the valves strigulose with white or black hairs, transversely rugulose-reticulate; ovules 5—8.
Distribution and Ecology - Sagebrush plains, dry hillsides, and gullied bluffs, sometimes in great abundance on over-grazed pastures, in stiff alkaline clay, black shale, or sandy clay overlying sandstone, 6500—8750 feet, locally common on the west slope of the Rocky Mountains in Colorado, about the headwaters of the Yampa, Grand, and thence south to the middle Gunnison and upper San Juan Rivers, extending north along Vermillion Creek just into southern Sweetwater County, Wyoming, west into the Uinta Basin and foothills of the La Sal Mountains in extreme eastern Utah, and south and southwest to the upper Little Colorado in northwestern Apache County, Arizona, and McKinley County, New Mexico, and to the Rio Grande drainage at the head of Rio Puerco in Sandoval County.—Map No. 45—May to July.
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Discussion
The Hayden milk-vetch is remarkable for the great number and small size of its nodding, retrorsely imbricated flowers which are disposed in elongate, cylindric racemes of a finger’s thickness. In New Mexico and southwestern Colorado the stems are usually diffuse and form low, leafy clumps from which the inflorescences arise vertically like candles; elsewhere the stems are as often erect and ascending in the manner of var. bisulcatus in the Prairie States. The hairs on the small, cross-reticulate pod vary from white to black.
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Objects
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Distribution
Colorado United States of America North America| Wyoming United States of America North America| Utah United States of America North America| Arizona United States of America North America| New Mexico United States of America North America|