Monographs Details: Astragalus lentiginosus var. micans Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.
Description:Variety Description - Strong perennial, the stems numerous, erect or the outer ones ascending in well-furnished clumps up to 5-7 dm. in diameter, becoming indurated or subligneous at base, the stems and herbage silvery- or white-silky, very densely villous- tomentulose with a coat of shorter, curly and longer, straighter, ascending, lustrous hairs up to 1.1-2 mm. long; leaves 4.5-9.5 cm. long, with 11-17 narrowly to broadly obovate or ovate, more rarely rhombic-suborbicular, truncate-emarginate to subacute leaflets 5-14 mm. long; peduncles stout, erect, 4.5-9 cm. long; racemes loosely (12) 20-35-flowered, the axis (3.5) 4.5-10 cm. long in fruit; calyx 6-7.6 mm. long, densely silky-villosulous with white and some fuscous hairs, the tube 4.6-4.9 mm. long, about 3 mm. in diameter, the teeth 1.4-2.6 mm. long; petals distally suffused with pink-lavender; banner ovate-cuneate, 12.2-14.3 mm. long, 8.4-10 mm. wide; wings 12.3-12.6 mm., the claws ± 4.7 mm., the blades 2.4-2.7 mm. wide; keel 9.6-10 mm., the claws 5 mm., the blades ± 5 mm. long and 3 mm. wide; pod obliquely ovoid, inflated, 1.5-2 cm. long, 0.8-1 cm. in diameter, contracted distally into an erect, unilocular beak 2.5-4 mm. long, the valves stiffly papery, not mottled, very densely silky-villous-tomentulose, the septum complete, 2.7-3.4 mm. wide; ovules 23-28.
Distribution and Ecology - Forming large clumps scattered over the lower slopes of mobile dunes, ± 3050-3100 feet, south end of Eureka Valley, Inyo County, California.—Map No. 132.—April to June.
Discussion:Like var. coachellae, which it most nearly resembles in its silken but even longer and denser vesture, var. micans is believed to represent an offshoot from var. variabilis which has acquired a certain individuality (or is at least enabled to maintain it) because of physical isolation in a desert basin walled about by formidable mountain barriers. The forms of A. lentiginosus geographically nearest to var. micans are var. Fremontii, quite common in the foothills of the Inyo and White Mountains, but easily identified by the smaller flower, less robust habit of growth, and probably always shorter life-span; the prostrate and quite different var. semotus, found at greater elevations, which need not concern us; and var. variabilis itself which extends north to Owens Lake in southern Inyo County, and is represented there by a winter-annual form with much shorter (even though silvery) pubescence, short calyx-teeth, and relatively small flowers which are symptomatic of intergradation into var. Fremontii. From specimens seen when only a few months old, I thought the petals to be paler than is usual in var. Fremontii or var. variabilis, whitish or ochroleucous tinged with pinkish-lavender in the distal half or third. The variety is associated with Ectospermum Alexandrae Swallen and Oenothera deltoides subsp. eurekensis Munz & Roos, described from the same place. The evening-primrose, interestingly enough, is perennial as is var. micans although derived from a species usually annual or monocarpic, or at least of short duration. As pointed out in the original description, var. micans is the most robust and long-lived among nearly related forms of the freckled milk-vetch.
California United States of America North America