Astragalus Beckwithii

  • Title

    Astragalus Beckwithii

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Astragalus beckwithii Torr. & A.Gray

  • Description

    243.  Astragalus Beckwithii

    Caulescent but variable in stature, glabrous or nearly so but the leaflets often thinly ciliate, and the bracts, raceme-axis, and inner face or tips of the calyx-teeth beset with a few straight, appressed hairs up to 0.3-0.6 mm. long, those of the inflorescence usually black, the herbage thick-textured, green, pale green, or glaucescent; stems decumbent and ascending from the root-crown or shortly forking caudex, 0.2-3.5 (7) dm. long, simple or bearing 1-3 branches or spurs at the lowest axils; stipules herbaceous, the lowest becoming papery, 1.5-10 mm. long, the lower ones amplexicaul-decurrent around half to the whole stem’s circumference, the upper ± semiamplexicaul, with deltoid or triangular, often recurving blades; leaves (2) 4—15 cm. long, petioled but the upper ones shortly so, with (7) 11-27 suborbicular, broadly oval, obovate, or rhombic- elliptic, obtuse, retuse, or sometimes mucronulate, flat leaflets 3—25 mm. long; peduncles erect or incurved-ascending, 3—14 cm. long, shorter than the leaf; racemes loosely but shortly 7—16-flowered, the flowers ascending at a wide angle, the axis 1-7 cm. long in fruit; bracts membranous or early becoming so, ovate or lanceolate, 1.5-7.5 mm. long; pedicels at anthesis slender, ascending, 1-2.5 mm. long, in fruit either ascending or arched outward, 2—3.5 mm. long; bracteoles commonly 2, sometimes conspicuous; calyx 7—13.5 mm. long, the subsymmetric disc 0.9—1.5 mm. deep, the tube 3.5—6.3 mm. long, (2.9) 3.2—5.2 mm. in diameter, the subulate or lanceolate teeth from half as long to slightly longer, the whole becoming papery, marcescent unruptured; petals ochroleucous, or purple with whitish wing-tips, rarely almost white; banner abruptly recurved through ± 90 °, 16.5-21 mm. long, broadest either above or below the middle, the blade ovate, obovate, or obscurely fiddle-shaped; wings 15-20 mm. long, the claws 6.5-9 mm, the oblanceolate or narrowly oblong-elliptic, obtuse or rarely subemarginate, straight or slightly incurved blades 10—13.5 mm. long, 2.6—4 mm. wide, keel 11.5-15.5 mm. long, the claws 6.2—8.5 mm., the half-obovate blades 5—7 mm. long, 2.8-3.8 mm wide, abruptly incurved through 90-100° to the deltoid, sometimes obscurely porrect apex; anthers (0.6) 0.65—0.85 mm. long; pod ascending, spreading, or somewhat declined, elevated on a stout, straight gynophore 1.5-5 mm. long, obliquely ellipsoid, oblong- or ovoid-ellipsoid, (1.5) 2—3 cm. long, 6—12 mm. in diameter, sharply incurved or bent (mostly at or below the middle) through 45-135 (180)°, usually acute at both ends, ± obcompressed and dorsally flattened or sulcate below the laterally compressed, triangular beak, keeled ventrally by the prominent, narrowly but sharply wing-margined suture, the fleshy, glabrous, pale green or glaucescent and often brightly mottled valves becoming stiffly leathery, brownish or stramineous, inflexed as a narrow, sometimes sub- obsolete septum up to 1 (1.5) mm. wide, this usually broadest just below the beak and becoming narrower or disappearing downward; ovules (18) 25—41; seeds light or dark brown, smooth but dull, 2.3-3.4 mm. long.