Astragalus musiniensis

Perennial but sometimes flowering the first season, with a long, woody taproot, the few or solitary stems reduced to thick, scarcely elongating, cylindric or turbinate crowns beset with imbricated stipules and stiff, recurved leaf-bases, the herbage densely strigulose, strigose, or subpilose with straight or nearly straight, appressed and some narrowly ascending, basifixed (or a few basally spurred and incipiently dolabriform) hairs up to (0.5) 0.6—1.25 (1.4) mm. long, the leaflets gray or silvery, equally pubescent on both sides; stipules firmly papery, becoming brown, prominently nerved, glabrescent in age, (3.5) 5—10 mm. long, semiamplexicaul, with erect, lanceolate or lance-acuminate blades; leaves radically tufted, (1.5) 2.5-12 cm. long, erect and spreading on stiff petioles, with 3-5 (or in some early leaves only 1) elliptic, oblong-elliptic, lanceolate, or broadly rhombic, acute or subacute, flat, subsessile but readily disjointing leaflets (0.5) 1-3 (3.5) cm. long, these approximate on a rachis 2-12 mm. long or, when only 3, subpalmate; peduncles stout, 1.5-6 cm. long, shorter than the leaves, ascending at anthesis, arcuate-procumbent in fruit; racemes loosely but shortly 1-4 (6)-flowered, the axis scarcely elongating, 2-10 mm. long in fruit; bracts firmly papery, ovate or lance-acuminate, 1.6-4 mm. long; pedicels ascending, straight or nearly so, at anthesis 1.2-2.5 mm., in fruit thickened, 1.6-4 mm. long; bracteoles 0; calyx 13-15.5 mm. long, strigose-pilose with subappressed or loosely ascending, black and white or all white hairs up to 1-1.8 mm. long, the oblique disc 1.5-2 mm. deep, the cylindric (sometimes upwardly a little constricted) tube 10.5-12.7 mm. long, 3.5-5.2 mm. in diameter, the subulate teeth (1.5) 2-3.6 (4) mm. long; petals pink-purple, the claws and the striate lozenge in the fold of the banner paler or whitish; banner gently recurved through ±40°, broadly oblanceolate-spatulate, shallowly notched, 22-28 mm. long, 8.5-14 mm. wide; wings 21-25 mm. long, the claws 12-14.2 mm., the narrowly oblong or lance-oblong, obtuse, straight or distally incurved blades 10-12.2 mm. long, 2.4-3.6 mm. wide; keel (18) 19-22.7 mm. long, the claws 11.8-15 mm., the gently lunate blades 7.6-9 mm. long, 3-4 mm. wide, gradually incurved through 45-85° to the blunt, rounded apex; anthers (0.65) 0.7-0.9 (1) mm. long; pod ascending (humistrate), obliquely ovoid- acuminate, (1.5) 2-3.6 cm. long, (0.8) 1—1.7 cm. in diameter, obcompressed and shallowly sulcate ventrally in the lower ½-??, thence incurved through 40-90° into the laterally compressed, triangular or triangular-acuminate beak, the succulently fleshy valves at first thinly hirsutulous to silvery-villous-hirsute (the hairs ascending and up to 0.6-2 mm. long), often less densely pubescent or glabrescent in age, ultimately brownish-stramineous with purple- or pink-suffused cheeks, the ripe walls differentiated into a thin, smooth or faintly reticulate (perhaps eventually exfoliating?) exocarp, a thin endocarp, and a mesocarp of cellular-spongy tissue at least 1.5-2 mm. long (thickest toward the lateral angles of the fruit), not inflexed; dehiscence apical, through the beak, after falling, ovules (33) 36-53; seeds chestnut-brown, pitted, wrinkled, or both, scarcely lustrous, 2.8-3.2 mm. long.—Collections: 14 (viii); representative: Jones (from Spring Glen) in 1896 (GH, NY, POM); Ripley & Barneby 8611 (CAS, NY, RSA, UTC); Barneby 12,697 (CAS, NY, RSA), 12,750 (CAS, RSA).

Gullied knolls and stony clay benches among junipers, on shale, sandstone, or gravelly alluvia, 4700-7000 feet, uncommon but well distributed around the west and north periphery of the Colorado Basin south of Tavaputs Escarpment, in the drainage of the upper Price, San Rafael, Fremont, Escalante and Grand Rivers, eastcentral Utah.—Map No. 84.—May and June.

Astragalus musiniensis (of Musinia Peak, a summit of the Wasatch over 20 miles w of the type-station) Jones in Proc. Calif. Acad. Sci. II, 5: 671. 1895 ("Musiniensis").—"No. 5454a.

June 18, 1894, two miles south of Ferron, Utah, on clay slopes, at about 6000° alt."—Holotypus, POM!—Xylophacos musiniensis (Jones) Rydb. in Bull. Torr. Club 40: 49. 1912 ("musinensis").

Astragalus musiniensis var. newberryoides (resembling A. Newberryi) Jones, Rev. Astrag. 212. 1923 ("Newberryioides").—"A common form from Thompson’s Spring and the San Rafael Swell in Utah..."—No spm. found labeled "Thompson’s Spring"; lectotypus, collected May 12, 1914, in the San Rafael Swell, Jones, POM!

Like the preceding species, with which it has much in common up to the fruit, A. musiniensis is a sharply defferentiated astragalus. The pithy texture of the ripe pod, formed as sap is withdrawn from the large cells of the mesocarp, is reminiscent of A. Chamaeleuce which occurs in similar environment but only rarely in the same range. As compared with the Ferron milk-vetch A. Chamaeleuce has a slender root-crown devoid of marcescent petioles, more numerous, smaller leaflets, and a less prominently beaked, purple-spotted or -mottled pod. Young, acaulescent, flowering specimens of A. Chamaeleuce can be distinguished by the dolabriform attachment of all the hairs. Jones (1923, p. 212) pointed out the many features common to A. musiniensis and A. Newberryi. They differ consistently in characters of the pod already stressed in the subsectional key, and are vicariant in range. The following species is somewhat intermediate between them.