Monographs Details: Astragalus lentiginosus var. antonius 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 - Strongly perennial, with prostrate or diffuse stems (0.7) 1.5-3 dm. long, closely related to and resembling the last, but the stems and herbage densely strigulose with subappressed hairs up to 0.4—0.6 mm. long, cinereous or silvery- canescent, the leaflets pubescent on both sides, sometimes more densely so above than beneath; leaves 3—8 cm. long, with 11—19 (21) obovate or elliptic, obtuse or emarginate, flat or loosely folded leaflets (2.5) 4—11 mm. long; peduncles (1) 2-5.5 cm. long; racemes ± 10-15-flowered, the axis (0.5) 1-4 (5) cm. long in fruit; calyx 4.2—5.5 mm. long, white- or pardy black-strigulose, the tube 3.2-4 mm. long, 1.8—2 mm. in diameter, the teeth 0.8—1.4 mm. long; petals purple, perhaps sometimes pale, the color fugacious; banner 9-10.5 mm. long; wings 7.9-10 mm., the blades 4.8-6.1 mm. long; keel 7.2-8.2 mm. long, the blades 3.7—4.3 mm. long; pod as in the preceding, 1.4-2.2 (3) cm. long, 1-1.6 (1.8) cm. in dimaeter; ovules 20—26.
Distribution and Ecology - Dry slopes in open yellow pine forest, 5000-8500 feet, known only from the slopes of Mt. San Antonio (Old Baldy) and the Blue Ridge, east end of the San Gabriel Mountains, in eastern Los Angeles and adjoining San Bernardino Counties, California.—Map No. 128.—Late April to July.
Discussion:The var. antonius resembles the preceding at every point except for the gray or silvery vesture of the leaves, the usually flat rather than characteristically crowded and folded leaflets, and the slightly smaller flower which seems to be of a fairly lively shade of purple when fresh. The range of the two varieties sierrae and antonius collectively coincides almost exactly with that of A. bicristatus and (except for a southerly extension to the Santa Rosa Mountains) with that of A. leucolobus. This common pattern of dispersal must have been determined by one set of circumstances, but whereas the last two species have remained monomorphic in their bicentric ranges, the sensitively plastic freckled milk-vetches have differentiated out into perceptibly different forms.
California United States of America North America