Astragalus curvicarpus (A.Heller) J.F.Macbr.
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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(1): 1-596.
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Family
Fabaceae
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Scientific Name
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Type
"Sierra Co. (Lemmon) and adjacent mountains of Nevada (Watson)."— Holotypus, Lemmon 621 in 1874, GH! istotypus, K! paratypi, Watson 282, from the Toyabe and Pah-Ute Mountains, GH, NY, US!
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Description
Species Description - Commonly robust and leafy, sometimes quite slender, with several or many decumbent or diffusely ascending stems arising from the knotty root-crown or shortly forking caudex at or just below soil-level, the herbage varying from loosely strigulose to villosulous with curly, incumbent, or sometimes appressed hairs up to 0.25-0.5 mm. long, in one var. nearly glabrous, in consequence varying from cinereous to deep green, the leaflets ± bicolored, yellow-green above; stems 1.5-4 (5) dm. long, leafless at base, simple or commonly branched or spurred at 1-several nodes preceding the first peduncle, flexuous or zigzag distally; stipules (1) 1.5-5 mm. long, the lowest scarious or early becoming so, decurrent around a little more than half the stem’s circumference, the median and upper ones herbaceous, mostly narrower, with deltoid or triangular-lanceolate, commonly reflexed blades; leaves 2.5-9 cm. long, all but the lowest subsessile, with ascending or sometimes divaricate rachis and (7) 9-19 (21) obovate-cuneate, oblong- obovate, or -elliptic, or broadly oblanceolate, retuse or truncate, more rarely elliptic-oblanceolate and obtuse, flat or loosely folded leaflets 3-18 (23) mm. long; peduncles erect or arcuate-erect, 4-15 cm. long, nearly always surpassing the leaf; racemes (5) 10-25 (35)-flowered, loose at full anthesis, the flowers nodding, the axis 2-10 (13) cm. long in fruit; bracts membranous or membranous-margined, ovate-acuminate, or lance-subulate, 0.7-2.5 mm. long; pedicels slender, at anthesis ascending, 1-2.2 mm. long, in fruit either ascending or a little arched outward, or sometimes straight and divaricate, 1.4-3.5 mm. long; bracteoles usually 0, minute when present; calyx 6.1-13.6 mm. long, villosulous or strigulose with white or black hairs, the disc set at an angle to the tube, the pallid, membranous, somewhat tumid tube deeply and broadly campanulate to broadly cylindric, straight or slightly concave dorsally, strongly convex ventrally and gibbous-saccate or truncate behind the pedicel, the triangular to broadly deltoid teeth 0.4-2.3 mm. long, the ventral pair broadest, but either longer or shorter than the rest, the whole becoming papery, marcescent unruptured; petals ochroleucous, clear white, or lemon- yellow; banner 13.6-21 mm. long, rhombic-oblanceolate or -ovate, tapering downward into a long claw curved conformably with the calyx, the blade commonly recurved through ± 45°, in one var. poorly developed and abruptly folded back distally as in A. collinus; wings a little shorter (longer) than the banner, the oblong-oblanceolate or -obovate, obtuse blades nearly straight to gently incurved; keel 9.4-15.2 mm. long, the half-obovate blades incurved through 85-100° to the bluntly deltoid apex; anthers 0.5—0.9 mm. long; pod pendulous (from horizontal peduncles vertically divaricate), stipitate, the straight, slender stipe 6-20 mm. long, the narrowly oblong body 1.4-3.5 cm. long, 2.7-4.5 mm. in diameter, crescentic, falcate, hamate, or more rarely coiled through 1½ spirals, cuneate or cuneately tapering at base, cuspidate at apex, strongly compressed, bicarinate by the salient, cordlike sutures, the lateral faces low-convex toward the dorsal edge, the somewhat fleshy, green or purple-spotted valves becoming brownish-stramineous, stiffly papery or thinly leathery, prominently cross-reticulate, villosulous or glabrous, not inflexed; dehiscence of the section, the sutures tending to separate from the valves in age; ovules 14—25 (28); seeds drab or olivaceous, smooth but dull, (2) 2.3-3.8 mm. long.
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Discussion
The sickle milk-vetch, A. curvicarpus, is a coarse but rather handsome astragalus, readily recognized by its nearly always broad truncate or retuse leaflets, nodding white to lemon- yellow flowers with basally pouched calyx, and stipitate, laterally flattened, usually much- incurved pods. Over the greater part of its range in the Great Basin it varies little; however, along the streams flowing north to the Columbia River in northcentral Oregon, it has given rise to two usually well-differentiated but marginally intergradient geographic races, differing in details of the vesture and flowers.
The name A. Whitedii, a synonym of A. sinuatus, a local species found only in eastern Washington well to the north of A. curvicarpus, was applied to this species for several decades (Barneby, 1956, p. 486) and is still current in some modern floras.