Astragalus diphacus S. Watson, Proc. Amer. Acad. Arts
Creators: name: Castillón, Eduardo Estrada
name: Quintanilla, José Ángel Villarreal
name: Delgado-Salinas, Alfonso
name: Rebman, Jon P.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Fabales
Fabaceae
Astragalus
Astragalus diphacus

description: 20. Astragalus diphacus S. Watson, Proc. Amer. Acad. Arts 17: 342. 1881–82   
 Type:— MEXICO, San Luis Potosi, San Miguelito Mountains, 1876, Schaffner 816 (holotype: GH 00059411 digital image!; isotype: NY 0005379 digital image!).   
 Hesperastragalus diphacus (S. Watson) Rydb., Bull. Torrey Bot. Club 53(3): 166. 1926.   
 Perennial. Stems up to 45 cm long, commonly decumbent or prostrate, but occasionally the distal parte erect; tiny strigose, the trichomes 0.15–0.4 mm long, appressed. Stipules 1.3–4.5 mm long, semi to completely clasping, not connate, triangular to lanceolate. Leaves 2–9 cm long; leaflets 9–25, 2–12 mm long, linear or oblanceolate, obtuse apically, mucronate, glabrate o subglabrate abaxially. Peduncles 3–13 cm long, incurved, humistrate with age, when fruit ripen; the racemes up to 8 cm long, dense, flowers 10–20, soon deflexed. Flowers yellow-cream, purple, greenpurple, the wings and keel red-violet, banner with red-violet veins; the calyx 4–5.8 × 2–2.5 mm long, strigose, commonly with black trichomes or mixed with white trichomes, rarely, the white ones denser, the tube 2.5–3.3 mm long, the teeth 1.3–2.8 mm long, subulate; the banner 7–9.8 × 3.5–5.9 mm, recurved, ovate, obovate to rhombic, briefly retuse; the wings 7–10 × 1.5–2.5 mm, the claw 2.2–3.3 mm long, the blade 4.7–7.1 mm long; the keel 5.1–6.9 × 1.8–2.7 mm, the claw 2.3–3.4 mm long, the blade 3–4 mm long, obovate. Pod 5–9.3 × 5–7.7 mm, sessile, ascendant, spreaded or deflexed, sub-globose, rarely oblong to elliptic or wider than long, inflate, stiff, constricted and forming two similar cavities, always retuse at both ends, and, a minute mucron at distal end, sulcate in both sutures, the valves thin papery but leathery with age, minutely strigose, yellowish, reddish to green, becoming black when aging, slightly or evidently reticulate; ovules 8–18; seeds 1.6–2.3 mm long, olive-green to brown, sometimes with purple tones.   
 Distribution:— Endemic to Mexico; restricted to the north of Mexico. Nuevo León (Galeana), Durango (Súchil and Vicente Guerrero), San Luis Potosí (San Luis Potosí, Villa de Reyes, Charcas and Villa de Arriaga), and Zacatecas (Zactecas City, Guadalupe, Ojo Caliente and Sombrerete) (Fig. 6).   
 Habitat:— Gravel, and calcareous, deep to shallow soils; arid grasslands of navajita; desert scrubland; abandoned cultivated areas; oak-pine forest; oak scrubland; oak forest with acacia; oak-forest; semi-arid pine forests; pine-juniper forest; plains with open vegetation, degraded grazing slopes; grass - Juniper associations; thorny scrublands; desert scrub; oak scrublands; Pine-Juniper forests; pine-oak-walnut association; abandoned farming fields; 1850–2400 m.   
 Comments:— Particular species to group a set of characteristics in a pod, inflate, rigid, somewhat compressed dorsally, sometimes wider than longer, retuse at both ends and minute mucronate at distal sinus. No other species of Astragalus presents this set of characters in a single pod.   
 Specimens examined:— COAHUILA: 15 July 2018, E. Estrada 22926 (CFNL). DURANGO: 22 September 1982, Km. 8 Carretera V. Guerrero-Súchil, M. González E. 1054 (CIIDIR, IBUG, IEB, MEXU); 31 July 1984, Súchil, Mirador El Fortín, cercanías, por salida de El Pedernal,, S. González 2905 (CIIDIR, IBUG); 13 August 1984, S. González 2915, S. Acevedo (CIIDIR, IEB); 13 July 1990, Predio las Bayas de UJED, 93 km al S de Durango, S. González 4499, A. García (CIIDIR, MEXU); 22 July 1990, MpIo. De Súchil, San Juan de Michís, camino a Piedra Herrada, Reserva de la Biosfera La Michilía, S. González 4618, R. Spellenberg (CIIDIR, IEB, MEXU); 25 July 5 - VIII 1906, Otinapa, E. Palmer 394 (NY); 31 July 1984, mpIo. Súchil, Mirador el Fortín, S. González 2905 (CFNL, CIIDIR); 22 July 1990, Ca. 20 air km SSW of Vicente Guerrero on road to San Juan de Michilia, 7 road mi. S of Suchil, 1/ 4 mi. N of Mirador El Fortin, R. Spellenberg 10268, S. González (MEXU, NY); 15 August 1959, 54 miles southeast of Durango, U. T. Waterfall 15559 (NY). NUEVO LEÓN: 16 July 1987, 1 km al NO del Ejido San José, La Joya, E. Estrada 1239 (MEXU, NY); 30 June 1991, Ejido El Orito, Galeana, E. Estrada 2027, J. Fairey, C. Schoenfeld (IEB, NY); 15 May 2003, 2 km de San Ildelfonso, Galeana, E. Estrada 15646 (CFNL, MEXU); 2 June 2000, Sierra Madre, Rincón del Jardín, camino Los Lirios-Laguna de Sánchez, cerca del límite con Coahuila, J. A. Villarreal 9010, M. A. Carranza, I. Ramírez (ANSM); SAN LUIS POTOSÍ. 1879, Ex convalli San Luís Potosí, J. G. Schaffner (NY); 13 September 1961, Puerto de la Huerta Carretera SLP-Rio Verde, A. Gómez 380 (NY); 8 November 1963, 2 miles east of Sombrerete, H. D. Ripley 13460, R.C. Barneby (NY 15 August 1959, 11 miles northwest of Sombrerete U. T. Waterfall 15565 (NY); VII August 1934, San Luis Potosi, Charcas, Mexico, C. L. Lundell 5123 (TEX-LL, US); 1989, Las Terrazas del Cono, Ejido Nuevo Centro de Población de la Paz, Mpio. Salinas, A. Gómez s.n. (IEB). ZACATECAS: 8 July 1971, Along Mexico Highway 49 below San Francisco los Flores, a small village south of the highway about 8.5 miles northwest of Sombrerete, the road to San Francisco being opposite the one to Providencia, about 1 mile south of Mexico Highway 49, J. L. Reveal 2670, W. J. Hess, R. W. Kiger (NY, TEX-LL, US);; 20 August 1974, Just west of the city of Zacatecas, R. W. Spellenberg 3803, J. Syvertsen (ENCB, NY, TEX-LL); 5 September 1975, Along the highway immediately W of Cd. Zacatecas, R. Spellenberg 4074, J. Willson, T. Feather (ENCB, NY); 17 October 1965, S end of Sierra Papanton, e. of El Calabazal, H. D. Ripley 14153, R. C. Barneby (NY); 6 November 1963, About the city of Zacatecas, H. D. Ripley 13453, R.C. Barneby (NY); 25 October 1888, Hills of Zacatecas, C. G. Pringle 1753 (NY); 8 November 1963, 2 miles east of Sombrerete, H. D. Ripley 13460, R. C. Barneby (NY, US); 15 August 1959, 11 miles northwest of Sombrerete, U. T. Waterfall 15565 (NY); 9–11 October 2005, La Jaula de Abajo, nopalera silvestre, Mpio. De Pinos, L. A. García-R. 1382 (IBUG).
description: Published as part of Castillón, Eduardo Estrada, Quintanilla, José Ángel Villarreal, Delgado-Salinas, Alfonso & Rebman, Jon P., 2023, The genus Astragalus (Leguminosae: Papilionoideae: Galegeae) in Mexico, pp. 1921-1935 in Phytotaxa 586 (1) on pages 1921-1935, DOI: 10.11646/phytotaxa.586.1.1, http://zenodo.org/record/7703999