Astragalus racemosus Pursh
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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
"In Upper Louisiana. Bradbury."—Holotypus, labeled "Louisiana, Bradbury. Pursh’s specimens," PH! isotypus, dated 1811-12, BM!
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Description
Species Description - Coarse, leafy herbs of stout or moderate stature, with a woody taproot and knotty, multicipital root-crown at or just below soil-level, thinly to quite densely strigulose with filiform or flattened, appressed hairs up to 0.35-0.65 mm. long (rarely a few longer spreading ones up to 1 mm. long), the thick-textured herbage green or subglaucescent, sometimes cinereous in youth, the leaflets glabrous and often minutely papillate above; stems several or numerous, erect and ascending in clumps, (1.5) 2-6 dm. long, simple only when slender, more commonly branched or spurred at 1-6 nodes preceding the first peduncle, naked and usually hollow at base; stipules scarious or early becoming so, 3-12 mm. long, the lowest often broader than long, amplexicaul and connate into a short, subtruncate or bidentate, fragile, often early ruptured sheath, the median ones progressively less united upward along the stem, the uppermost free or nearly so, with deltoid or triangular, spreading or deflexed blades; leaves (4) 5-15 cm. long, the lowest shortly petioled, the rest subsessile, with (9) 11-29 (31) lance-elliptic to ovate, mostly obtuse and mucronulate, sometimes (in upper leaves, rarely all) linear- lanceolate or -elliptic and acute or acuminate, flat or loosely folded leaflets (0.5) 1-3.5 cm. long; peduncles erect, commonly stout, (3) 4-11 cm. long, usually a little shorter than the leaf; racemes (15) 20-70-flowered, commonly dense (but sometimes quite loose) at early anthesis, the flowers nodding and ± retrorsely imbricated, the axis elongating, (3) 5-15 (22) cm. long in fruit; bracts scarious, lanceolate or lance-caudate, (1.5) 3-9 mm. long; pedicels slender, at anthesis straight and narrowly ascending to arcuately spreading, 2-3.5 mm. long, in fruit arched outward, decurved, or irregularly contorted, 3-8 mm. long; bracteoles 0-2; calyx 7.3-19 mm. long, pallid or rarely pinkish, finely strigulose with white, more rarely partly or wholly black hairs, the strongly oblique disc 0.9-1.5 mm. deep, the campanulate tube 4.7-9 mm. long, 3.2-5.5 mm. in diameter, the subulate or subulate-setaceous teeth 1.5-10 mm. long; petals white or ochroleucous (concolorous), or whitish with keel-tip, wings, or base and tip of banner-blade tinged or veined with pale lilac or pink-purple; banner recurved through ± 45° (or further in age), oblanceolate, with long-cuneate claw proximally incurved to conform with the oblique or gibbous base of the calyx, 14-20.5 mm. long, 6-10.5 mm. wide; wings 12.5-19 mm. long, the claws 5.2-8 mm., the narrowly oblong-oblanceolate, obtuse or obscurely emarginate, nearly straight or slightly incurved blades 9-12.4 mm. long, 2.2-3.7 mm. wide; keel 10.8-15.2 mm. long, the claws 4.7-8 mm., the lunately half-oblong-obovate blades 7.2-10 mm. long, 2.6-3.8 mm. wide, incurved through 85-95° to the rounded apex; anthers (0.6) 0.65-0.9 mm. long; pod pendulous, stipitate, the slender, straight stipe 3.5-7 mm. long, the linear-oblong, lance-oblong, oblong-ellipsoid, or (in one var.) plumply oblong- ovoid body 1-3 cm. long, 3-8 mm. in diameter, cuneate at both ends, or at base varying from acuminate to subtruncate, cuspidate at apex, straight or gently curved either way, triquetrously compressed with acute ventral and narrow but blunt lateral angles, the 3 faces all flat, or the dorsal face (or all 3) shallowly concave, the thin, pale green, glabrous or rarely thinly strigulose valves becoming papery, stramineous, lustrous, delicately cross-reticulate, not inflexed, or inflexed as a rudimentary partition less than 0.3 mm. wide; ovules 12-22; seeds dark or chestnut- brown, smooth or nearly so, dull or lustrous, 2.6-3.3 mm. long.