Astragalus mollissimus var. marcidus (Greene ex Rydb.) 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(2): 597-1188.
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Family
Fabaceae
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Scientific Name
Astragalus mollissimus var. marcidus (Greene ex Rydb.) Barneby
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Type
"Type collected in the Davis Mountains, Texas, April 28, 1902, Tracy & Earle 319... " Holotypus, NY! isotypi, G, GH, MO, ND, TEX, US!`
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Synonyms
Astragalus marcidus Greene ex Rydb.
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Description
Variety Description - Closely resembling var. Bigelovii except for the small flower and pod, acaulescent or nearly so, densely villous, the longest hairs of the herbage up to 1.7-2.5 mm. long; leaves 5-15 cm. long, with 15-19 (21) leaflets 4-15 (20) mm. long; peduncles 3.5-11 cm. long; racemes 10-45-flowered, the axis 3-10 cm. long in fruit; calyx 6.S-9.9 mm. long, the tube 5.2-6.4 mm. long, 2.8-3.5 mm. in diameter, the teeth 1.6-3.5 mm. long; petals pink-purple; banner 11.8-16.3 mm. long, 4.2—8.3 mm. wide; wings 11—14.4 mm. long, the claws 5.2—7 mm., the blades 6.7-8.6 mm. long, 1.8-2.3 mm. wide; keel 9.9-12.5 mm. long, the claws 5.3-7.2 mm., the blades 5—6 mm. long, 2.3—2.7 mm. wide; pod 6—10 mm. long, 3—5 mm. in diameter, fully bilocular, villous-hirsute with hairs over 1 mm. long; ovules 12-16.
Distribution and Ecology - Open, gravelly hillsides and rocky stream beds, in volcanic soils, 5000-6350 feet, uncommon, known only from Jeff Davis and Presidio Counties, trans-Pecos Texas (Davis Mountains; Marfa; Chinati Mountains and vicinity).—Map No. 99.—April to July.
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Discussion
The var. marcidus is a comparatively rare form. It is evidently close to var. Bigelovii, having the same long vesture of loosely spreading hairs and the fully bilocular pod; but the pod and the flower are so strikingly smaller as to give a peculiar aspect to the plant. And no other variety of the woolly locoweed has so few ovules. The marcescent petals are not (as in many Eurasian astragali) attached by their claws to the staminal sheath, but merely tend to linger about the forming pod to which they are appressed by the sheathing calyx, a phenomenon by no means unique to the variety. The records of var. marcidus from Chihuahua (Hartman 605) and Coahuila (Palmer 559) listed by Rydberg are wrongly identified. The first is characteristic var. Earlei; and the second (with banner about 19 mm. long) seems to represent the more southern var. irolanus. In the Davis Mountains the two small-flowered woolly locoweeds, var. marcidus and var. Earlei, are sympatric, but the latter, by far the commoner, is easily distinguished by its short-pubescent pod unilocular in the beak.
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Objects
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Distribution
Texas United States of America North America|