61. Astragalus nothoxys A. Gray, Proc. Amer. Acad. Arts 4: 232. 1864

Type:— USA, Arizona, San Luis Mountain and Guadeloupe Canon, 1851, Thurber s.n. (holotype: NY00005814!; isotype: NY01268197!; syntype: E. K. Smith s.n. GH00058846 digital image!; isolectotype: Thurber s.n. GH00058845 digital image!) .

Tragacantha nothoxys Kuntze, Revis. Gen. Pl. 2: 946. 1891. — Oxytropis nothoxys M. E. Jones, Proc. Calif. Acad. Sci. ser. 2, 5: 677. 1895. — Spiesia nothoxys M. E. Jones, Proc. Calif. Acad. Sci. ser. 2, 5: 677, in syn. 1895. — Aragallus nothoxys A. Heller, Cat. N. Amer. Pl. 4. 1898. — Hamosa nothoxys Rydb., Bull. Torrey Bot. Club 54: 330. 1927.

Astragalus madrensis M. E. Jones, Rev. N.-Amer. Astragalus 274. 1923; Hamosa madrensis Rydb., N. Amer. Fl. 24(7): 426. 1929; Hamosa gooddingii Rydb., Bull. Torrey Bot. Club 54: 20. 1927; Astragalus gooddingii Tidestr., Proc. Biol. Soc. Washington 48: 40. 1935.

Perennial, sometimes of short duration. Stems up to 40 cm long, weak, prostrate or ascending distally, strigose to green-glaucos, trichomes up to 0.5 mm long, sometimes purplecolored basally. Stipules 1.5–5.8 mm long, semiclasping, not connate, triangular to lanceolate, sometimes pale purple. Leaves 2–11.5 cm long, leaflets 7–21, 2–15 mm long, ovate, elliptic, oblanceolate, wide-oblong, obovate to elliptic obovate, rarely some leaflets suborbicular, obtuse to mostly retuse, glabrate or almost so. Peduncles 3–15 cm long, ascendant to incurved, pendulous with age; the racemes 0.4–9 cm long, flowers 4–25. Flowers pink-lavender, pink, purple, rose-purple, turning blue when drying, sometimes the banner red-violet and basally white, sometimes with white tones in different parts; the calyx 5–7 × 2.1–3 mm, cylindric to cylindric-campanulate, strigose, trichomes white o white and black mixed, the tube 3.2–4.9 mm long, frequently purple, the teeth 1.4–2.7 mm long, subulates; the banner 8.5–12 × 5–7.7 mm, ovate to obovate, basally cuneate, subtruncate to retuse; the wings 8.5–11 × 1.7–3.6 mm, the claw 3.3–4.8 mm long, the blade 5.5–7.7 mm long, oblanceolate, oblong to obovate; the keel 6.8–8.4 × 1.2–2.3 mm, the claw 3.3–4.4 mm long, the blade 3.3–5.2 mm long, markedly incurved, almost in straight angle, distally acute. Pod ascendant, 13–22 × 2–6 mm, sessile o minute elevated above receptacle, linear to lanceolate, triquetrous (rarely the pod dorsoventrally compressed to somewhat bulged, wide-elliptic to wide-oblong, ventrally carinated, incurved, rounded at both ends, but with a small, narrow triangular), but its lateral faces not concave, but convex or little so, distally contracted in a short triangular beak, with the angles obtuse, dorsally narrowly sulcate, the valves papery, ochre to brown, strigose, softly reticulate, septum complete or almost so, the pod thence bilocular or almost so, apically ending in a 1–2 mm long beak, the valves stiffly papery, tan or light-brown, finely and perpendicularly reticulated, tiny and scattered pubescent, densely pilose with white trichomes, fully bilocular basally rounded; ovules 16–26; seeds 1.8–2.9 mm long, brown to dark brown, mitten shape, sometimes with purple tones, wrinkled, somewhat opaque.

Distribution:— Northwest Mexico; Sonora and Chihuahua. In Sonora, from northwest in Santa Ana and Magdalena, through Nogales, Cananea, and Naco to Aguaprieta and in the vicinity to Chihuahua, southeast, at the height of Yécora. In Chihuahua, from Casas Grandes, through Buenaventura, Gómez Farías, Namiquipa to Guerreo, La Junta and Cuauhtémoc. Also, in New Mexico and Arizona (USA) (Fig. 18).

Habitat:— Slopes with volcanic soils; stony, clayey and flooded soils; sand in wash; oak-mezquite-grassland; associated with overgrazed grasslands; grasslands with Prosopis-Quercus; oak forest; disturbed areas; desert shrubland with Acacia, Prosopis, Yucca, Gutierrezia, Opuntia; Quercus-Pinus-Juniperus forest; riparian areas with Salix; pineoak forest; streams; 1287–1981 m.

Comments:— In these areas, where several ecosystems converge, at least 18 species of Astragalus are reported, but only five of them have simple trichomes, clasping or semi-clasping stipules and triquetrous sessile pods ( A. gentryi, A. hartwegii, A. nothoxys, A. nuttalllianus and A. pringlei). A. nuttallianus can be distinguished by its few-flowered racemes (1–7); A. hartwegii is differentitated by its small calyx (3.2–4.8 mm); A. nothoxys, A. pringlei and A. gentryi can be discerned based on certain particular characters. Astragalus gentryi has irregularly graduated petals, the apex of the keel equals or surpasses the wings lenght, in the other two species, the wings are longer than the keel. Astragalus pringlei has leaves (1.5–4.5 cm) and peduncles (0.5–5.5 cm) shorter, the racemes with fewer flowers (3–12) and pod shorter (7–11 mm long).

Specimens examined:—CHIHUAHUA: 24 March 1975, 8.4 mi SW of Buenaventura, R. Spellenberg 3990 &, M. Spellenberg (NY) ; 12 April 1891, Puerta de St. Diego, C. V. Hartman 622 (NY) ; 11 September 1903, San Diego Canyon, M. E. Jones s.n. (CAS, NY) . SONORA: 19 March 1984, Along Highway 2, ca. 26 miles east of Agua Prieta and ca. 24 miles west of the state line at Puerto San Luis, A. C. Sanders 4719, W. Charlton, V. Way, McIntosh, Gibeau, Gould (NY) ; 28 March 1997, Maycoba, T. R. Van Devender 97-387, A. L. Reina (CAS, MEXU, USON) ; n.d., San Louis Mountains & Guadalupe Cañon, E. K. Smith s.n. (NY) ; 13 March 2000, A. L. Reina, G. 2000-123 B, T. R. Van Devender, R, A, Castillo G., M. A. Dimmitt (USON); 6 April 2008, Mpio. Santa Cruz, Rancho Los Fresnos Grassland Preserv, Upper Rio San Pedro drainajeadjacent to US border, B. Boyle 8092, D. Boss, K. Cranston (USON) ; 25 March 2005, Isolated Hill NE of Sierra Anibácachi, Rancho la Calera, ca. 10 km by air, SW of Agua Fría, T. R. Van Devender 2005-411, A. L. Reina G., M. Shieber, M. Klotz (USON) ; 18 May 2010, 51.2 km by air, E of Agua Prieta, Cuenca Los Ojos, Foundation property, A. L. Reina G. 2010-531, T. R. Van Devender (MEXU, USON) ; 9 April 2003, 4.7 km southeast of Naco on road to Cananea, T. R. Van Devender 2003-335, A. L. Reina, G. Anderson (MEXU, USON) ; 15 April 2006, Mouth of arroyo along beach at Barril, 48 mi E of Pozo Aleman, B. Boyle 7824, A. Estes, D. Hearn (USON) ; 13 March 2000, Restaurant La Palmita, 9.5 km W Restaurant of Puerto de La Cruz on Mex 16 ( Km 258 east of Cd. Obregón)north side of Mesa del Campanero, A. L. Reina G. 2000-1238 et al. (USON) ; 5 October 1996, 1.5 Km. al W de la Estación de Microondas del Cerro el campanero, A. Flores M. 5061, J. Sánchez (IEB, MEXU) ; 23 March 1979, 4 mi E of Yécora, G. L. Webster 23845 (MEXU) ; 20 May 1987, Puerto Cananea 13 km al W de Cananea, P. Tenorio L. 13545, C. Romero de T. (MEXU) ; 9 April 2003, 4.7 km southeast of Naco on road to Cananea, T. R. Van Devender 2003-335, A. L. Reina, G. Anderson (MEXU) ; 22 May 1987, Desviación a Naco de la Carr. Cananea-Agua Prieta, P. Tenorio L. 13618, C. Romero de T. (MEXU) ; 20 May 1987, 10 km al S de Cananea, Carretera a Arizpe, P. Tenorio L. 13583, C. Romero de T. (MEXU) .