Astragalus carminis Barneby

Authors

Rupert C. Barneby

Authority

Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.

Family

Fabaceae

Scientific Name

Astragalus carminis Barneby

Type

"Mexico. Coahuila: Canon de Sentenela on Hacienda Piedra Blanca, Municipio de Villa Acuña, 6 July 1936, F. Lyle Wynd & C. H. Mueller 556. .. "—Holotypus, US! isotypi, ARIZ, GH, MO, NY!

Description

Species Description - Rather slender, thinly strigulose with straight, appressed hairs up to 0.3-0.5 mm. long, the herbage pale green, the leaflets thin-textured and bicolored, green and glabrous above, pallid or subglaucescent and thinly pubescent beneath; stems several or numerous, ascending from the crown of a thick, woody taproot or from a shortly forking caudex, sometimes diffuse and trailing, 1.5-5 dm. long, simple or commonly branched or spurred toward the base; stipules thinly herbaceous or submembranous, the lowest becoming papery, 1.5—5 mm. long, the lowest small, deltoid, the upper ones broadly triangular to lance-acuminate, embracing ± ½ the stem’s circumference; leaves 3—8 (10) cm. long, slender-petioled but the upper ones shortly so, with (13) 17—27 oblong-obovate or obovate-cuneate, retuse or truncate-emarginate, flat leaflets 2—12 mm. long; peduncles erect or incurved- ascending, 4—9 cm. long; racemes loosely (4) 6—14 (20)-flowered, the flowers widely spreading and in age declined, the axis elongating, 1—6 (8) cm. long in fruit; bracts membranous, lanceolate or linear-setaceous, 1—2.5 mm. long, reflexed in age; pedicels at anthesis ascending, straight or distally arched outward, 0.5-1.7 mm. long, in fruit more strongly arched, a little thickened, 1-2 mm. long; bracteoles 0; calyx 4.4-5.3 (5.8) mm. long, loosely black- and white-stngulose, the oblique disc 0.7-0.8 mm. deep, the tube 1.6-3 mm. long, 2-2.6 mm. in diameter, the lanceolate or subulate teeth 1.6-3 (4) mm. long; petals bluish- or pinkish- purple, apparently pale; banner abruptly recurved through ± 90°, obovate-cuneate, notched, 7.6-10 mm. long, 4.5-6 mm. wide; wings (as long or slightly longer) 7.6-10 mm. long, the claws 2.3-3 mm., the linear-oblong or -elhptic, obtuse or erose-undulate, lunately incurved blades 6.4-8 mm. wide; keel 6.3-7.5 mm. long, the claws 2.3-3 mm., the broadly haff-elliptic blades 4-4.7 mm. long, 2.2-2.5 mm. wide, abruptly incurved through 90-95° to the sharply deltoid, slightly porrect apex; anthers 0.4-0.5 mm. long; pod declined or (from horizontal peduncles) spreading, the stipe 1-2.7mm. long, the body linear-oblong in profile, lunately or falcately incurved, 1.2-2.2 cm. long, 2.5-3.5 mm. in diameter, cuneately contracted at both ends, cuspidate at apex, triquetrously compressed, with nearly flat lateral and narrowly sulcate dorsal faces, carinate ventrally by the suture, the lateral angles obtuse, the thin, green, glabrous valves becoming papery, stramineous, delicately cross-reticulate, the complete or almost complete septum 1.1-1.6 mm. wide; ovules 12-16; seeds brown, smooth but hardly lustrous, 2-2.5 mm. long.

Distribution and Ecology - Streamsides and open slopes among pines and scrub-oaks, about (?) 5000-6500 feet, apparently not uncommon in the mountains of northwestern and western Coahuila (Sierra del Carmen, Sierra del Pino, Sierra Encantada, Sierra Madera, and Sierra Almagre); to be sought in adjoining Chihuahua and possibly in trans- Pecos Texas.—Map No. 51.—Late June to September.

Discussion

Early collections of A. carminis were identified and distributed as A. madrensis, a species which has turned out to be synonymous with A. (Micranthi) nothoxys and therefore easily distinguished by its slenderly acuminate keel-tip and by a pod truly sessile and deciduous from the receptacle. Although far removed geographically from other centers of speciation in its section, A. carminis has all technical characters of the Miselli. It might be sought among the Strigulosi, many of which are also Mexican and flower in the summer and fall months; but these have connate stipules at the base of the stems and (with two allopatric exceptions) a pod either semibilocular or decurved or both. A delicately pretty astragalus, the Carmen milk- vetch is recognized in its region by the rather numerous small leaflets of thin texture, the loose racemes of relatively small, pink flowers, and the narrow, drooping, trigonously compressed, glabrous pods which are more or less strongly incurved into a shallow crescent or sickle. The short stipe, often concealed by the marcescent calyx, is easily overlooked.

Distribution

Coahuila Mexico North America|