Monographs Details: Astragalus sepultipes (Barneby) Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.
Family:Fabaceae
Discussion:

352.  Astragalus sepultipes

Moderately stout or quite slender, with a woody taproot and knotty, shortly forking, subterranean caudex, strigulose-villosulous and villous-pilose with shorter, subappressed, together with longer, loosely ascending, somewhat wavy hairs up to 0.85-1.15 mm. long, the stems greenish, the herbage silvery- or cinereous-silky, the inflorescence densely villous; stems several 1.5-3.5 dm. long, slender, glabrous, buried for a space of 0.5-5.5 cm., thereafter either simple or branched at 1-2 nodes preceding the first peduncle, diffuse and ascending, flexuous or zigzag distally; stipules (2) 3-7.5 cm. long, the lowest ones small, connate through ± half their length into a pallid, scarious, glabrous sheath, the median and upper ones herbaceous above the base, amplexicaul and connate by a narrow scarious collar, with triangular-acuminate, spreading, dorsally pubescent blades; leaves divaricate and ascending, 2-8 cm. long, mostly shorter than the principal internodes, shortly petioled or the uppermost subsessile, with (7) 11-17 obovate-cuneate or broadly oblanceolate, retuse, or truncate and mucronulate, usually loosely folded leaflets (3) 4-14 mm. long; peduncles rather stout, incurved-ascending, (3) 5-12.5 cm. long, surpassing the leaf; racemes (10) 15-30-flowered, rather dense and ovate- oblong in early anthesis, looser in age, the flowers subhorizontal or ascending at a wide angle, the axis (2) 4-11 cm. long in fruit; bracts herbaceous, lanceolate or sublinear, 3-5 mm. long; pedicels at anthesis slender, ascending, 0.8-1.5 mm. long, somewhat thickened but hardly elongating in fruit, finally disjointing; bracteoles 0-2, minute when present and concealed by the vesture; calyx 8.6-13 mm. long, densely villous-villosulous with lustrous white hairs, the subsymmetric disc 1.1-1.6 mm. deep, the submembranous, purplish tube (4.7) 5.1-6.5 mm. long, 3.6-4.2 mm. in diameter, the linear-caudate, plumose-ciliate teeth 3.5-5.7 (6.5) mm. long, the whole becoming papery, ruptured, marcescent; petals pinkish-white, or pale lilac with whitish wing-tips; banner recurved through ± 40°, rhombically ovate-cuneate, notched, (12.7) 14.5-17.5 mm. long, 8.8-10.8 mm. wide; wings (11.1) 12-14 mm. long, the claws 4.8-6.6 mm., the straight, oblong, obliquely truncate or emarginate blades 7.2-8.8 mm. long, (2.2) 2.7-3.6 mm. wide; keel (10) 10.3-12.2 mm. long, the claws 4.8-7.2 mm., the lunately half-obovate blades 5.5-6.3 mm. long, 2.7-3.4 mm. wide, incurved through 90-95° to the rounded apex; anthers (0.6) 0.7-0.95 mm. long; pod loosely spreading-ascending or declined, sessile, deciduous, narrowly oblong in profile, gently incurved, 1.5-2 cm. long, 3.5-5.5 mm. in diameter, cuneate at both ends, cuspidate at apex, compressed-triquetrous, carinate ventrally by the suture, with almost flat lateral and narrower, shallowly sulcate dorsal faces, the thinly fleshy, finely twisted-villous valves becoming stiffly papery, stramineous, reticulate, inflexed as a complete septum 2-3.5 mm. wide; dehiscence apparently apical, perhaps also tardily basal; ovules (14) 16—20; seeds not seen.—Collections: 9 (i); representative: Alexander & Kellogg 2819 (DS, NY, US, UTC, WS); Barneby 11,327 (CAS, NY, RSA); L. S. Rose 58,070 (CAS).

Dry benches and canyon banks, in granite sand, among sagebrush in piñon forest, local but forming colonies at 6000-6500 feet in the east foothills of the Sierra Nevada from near Lone Pine north to Independence Creek, Inyo County, California.—Map No. 158.—May to July.

Astragalus sepultipes (Barneby) Barneby in Aliso 4: 136. 1958, based on A. Andersonii var. sepultipes (with buried foot, of the subterranean caudex) Barneby in El Aliso 2: 209. 1950.—"California: foothills west of Bishop, Inyo Co. ... 21 May, 1906 ...A. A. Heller 8357 ... "—Holotypus, CAS! isotypi, G, NY, P, US!

The Bishop milk-vetch, A. sepultipes, was described as a variety of A. Andersonii, but as now known from much more ample material it may be recognized by strong technical characters. The buried root-crown, silken rather than stiffly villous herbage, firm stipules and bracts, larger flowers, and more numerous ovules distinguish it from its relative at all stages of growth. The average plant is more slender and graceful than A. Andersonii, because of the greater development of the internodes, most of which surpass the leaves in length. The position of the resting buds below ground, in the context of the section evidently a specialized feature, is characteristic and constant, whether the plants are found on steep banks or on level ground, and cannot be attributed to accidental burial by shifting talus. Fully ripe fruits are still required to show the mode of fall and dehiscence, but there is little reason to anticipate anything original in these respects.

Although the flowers are relatively large, the Bishop milk-vetch is not one of the showy astragali. The petals are whitish faintly tinged with pink, or dull gray-lavender which appears almost truly gray in the strong desert light; the silvery-silky pubescence of the leaves makes an attractive contrast with the villous inflorescence. The plants have a quite individual grace. The species was first collected in 1897 by Marcus E. Jones (POM, UTC) near Lone Pine.