Astragalus newberryi A.Gray
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.
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Family
Fabaceae
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Scientific Name
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Type
"On the frontiers of Utah and Arizona, Newberry. Canon east of Glenwood, Sevier County, Utah, at 7000 ft., Lester F. Ward on Powell’s Expedition, 1875."—Holotypus, collected by Newberry at Camp 74, n. borders of Arizona... lat. 36° 30', in 1858, GH! isoty
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Description
Species Description - Dwarf or low, perennial but sometimes flowering the first season, the 1-several stems reduced to thick, obconic crowns crowded on the summit of a taproot and beset (after the first year) with a thatch of imbricated stipules and coarse, marcescent, recurving petioles, the herbage densely tomentulose with short, curly, and also (usually more abundantly, sometimes exclusively) silky-pilose or -strigose with longer, straight or nearly straight, rather stiff, lustrous hairs up to 1-2 mm. long, the longer hairs on the petioles and peduncles either loosely ascending or spreading, those of the leaflets either ascending or appressed (sometimes spreading late in the season), the inflorescence villous-pilose; stipules submembranous becoming scarious and ultimately brown and papery, ovate, lanceolate, ovate- or lance-acuminate, (3) 5-11 mm. long, semiamplexicaul; leaves (1.5) 3-13 (15) cm. long, with 3-13 (15) obovate, rhombic-elliptic, broadly oblanceolate, or rarely suborbicular, acute, obtuse, or sometimes retuse, flat, thick-textured, at length deciduous leaflets (3) 5-15 (20) mm. long; peduncles stout, (0.5) 1-10 cm. long, nearly always (usually much) shorter than the leaves, arcuate-procumbent in fruit; racemes loosely but shortly, often subumbellately (2) 3-8-flowered, the axis scarcely elongating, 0.3-2 (2.7) cm. long in fruit; bracts submembranous, greenish or purple-tinged, becoming pallid and papery, lanceolate or lance- acuminate, 3.5-10 mm. long; pedicels ascending, straight or nearly so, at anthesis 3 (4) mm., in fruit thickened, 2-3.5 (4.5) mm. long; bracteoles usually 0, rarely 2, exceptionally up to 4 mm. long; calyx (8) 9-20 mm. long, villous with loosely ascending (and often some shorter, curly) hairs up to 1 mm. long or more, the hairs of either sort being black, white, or of mixed colors, the subsymmetric or oblique disc 1-2 mm. deep, the membranous, pallid or purplish tube broadly to narrowly cylindric, or (in var. Blyae) deeply campanulate, the subulate or lance-subulate teeth (1.6) 1.9-6.5 mm. long; petals pink-purple with a pale lozenge in the fold of the banner, sometimes pale pink, or whitish tipped and margined with lilac or purplish-pink; banner recurved through ± 40°, broadly oblanceolate or rhombic-spatulate, shallowly or deeply notched, 14—32 mm. long; wings a little shorter, the narrowly lanceolate, obtuse or obliquely truncate blades nearly always gently incurved beyond the middle; keel 12—26 mm. long, the half- elliptic or lunately elliptic blades incurved through 40-85° to the blunt apex; anthers 0.45-0.95 mm. long; pod ascending, or spreading and incurved, humistrate, seated on an obconic boss or incipient gynophore up to 1.2 mm. long, obliquely ovoid or ovoid-acuminate, (1.3) 1.8-2.8 cm. long, 7-11 (13) mm. in diameter, rounded, broadly cuneate, or subtruncate at base, obcompressed and openly depressed-sulcate ventrally (and sometimes also, but more often merely flattened, dorsally), tapering or abruptly contracted distally into a shortly triangular or deltoid-acuminate, ± incurved or backwardly hooked, laterally flattened beak, the somewhat fleshy valves becoming leathery, ± 0.2—0.4 mm. thick and reticulate when ripe, densely (rarely thinly) tomentulose with short, curly hairs and villous- hirsute with longer, lustrous, spirally twisted, straight or nearly straight, spreading or widely ascending ones up to (2) 2.5—4.5 mm. long, the shorter hairs rarely sparse or almost wanting, the surface then visible between the longer villi; septum 0, but the dorsal suture sometimes a trifle thickened and raised within the cavity as a low ridge; dehiscence apical, through the gaping beak, after falling; ovules (20) 27-40 (46); seeds light or dark brown, sometimes almost black, smooth or punctate-rugulose but scarcely lustrous, 2.2-3.8 mm. long.
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Discussion
The Newberry milk-vetch is one of several intermountain astragali which bear pods so densely villous and tomentulose as to resemble bombycine cocoons or pellets of cotton. This is such a striking feature that it tends to overshadow the differences between the species. Except for the uncommon A. eurekensis, already mentioned in the subsectional key, A. Newberryi is alone in having a pod of this sort combined with a vesture of stiff, shining hairs (not entangled and cottony) and all stems reduced to thickened crowns beset with persistent leaf-bases. The species is variable in stature, in number of leaflets, in size of the flowers, and in curvature of the pod, but only one poorly differentiated geographic race seems to be sufficiently well stabilized to deserve taxonomic status.