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Astragalus chuskanus
(Chuska milkvetch)
[taxon report][distribution map][photos][line drawing]
Family: Fabaceae
Scientific Name: Astragalus chuskanus Barneby & Spellenberg
Synonyms: None
Vernacular Name: Chuska milkvetch
R-E-D Code: 2-1-2
Description: Matted perennial herb; stems spreading on ground (humistrate), freely branching, densely leafy, to 4 dm long; herbage densely hairy with soft, fine, basifixed hairs; stipules connate; leaves silvery-gray, 1.5-4 cm long; leaflets 9-15, obovate or oblong-elliptic, 2.5-9 mm long, 1-3 mm wide; racemes shortly but loosely 4-10 flowered; flowers pea-like; calyx about 5.5 mm long; petals whitish, fading to ochroleucous, often blushed with lilac or dull purple; pods lying on the ground, twisted on the stalk and ascending, sessile, obliquely semi-ovoid, pilosulous, 6 mm long (excluding the persistent style base), 3 mm wide. Flowers late May through July.
Similar Species: Astragalus chuskanus is distinguished from A. micromerius by its more robust habit, longer leaves, greater number of flowers, and slightly larger pods. Astragalus humistratus has dolabriform hairs versus basifixed hairs in A. chuskanus.
Distribution: New Mexico, San Juan and McKinley counties, Chuska Mountains; adjacent Arizona.
Habitat: Degraded Chuska sandstone in openings in montane coniferous forest above 1,650 m (5,500 ft).
Remarks: Astragalus chuskanus is often found on roadcuts and disturbed areas.
Conservation Considerations: Portions of the habitat of this plant are logged, but no studies have evaluated the effects of timber harvest on this species.
Important Literature (*Illustration):
*Barneby, R.C. and R. Spellenberg. 1987. A new species of Astragalus (Leguminosae) from northwestern New Mexico and adjacent Arizona. Brittonia 39(2):188-191.
Isely, D. 1998. Native and naturalized Leguminosae (Fabaceae) of the United States. Monte L. Beane Life Science Museum, Brigham Young University, Provo, Utah.
Information Compiled By: Daniela Roth, 1999
Agency Status:
