Astragalus giganteus S. Watson, Proc. Amer. Acad. Arts 1882
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 giganteus

description: 30. Astragalus giganteus S. Watson, Proc. Amer. Acad. 17: 370.1882   
 Type:— USA, Texas, Fort Davis, Westem Texas, 1881, V. Havard 32 (holotype: GH00058746 digital image!; isotype: US00004099 digital image).   
 Astragalus texanus E. Sheld., Minnesota Bot. Stud. 1: 65. 1894.   
 Astragalus giganteus E. Sheld., Bull. Geol. Nat. Hist. Surv. 9: 65. 1894.   
 Astragalus yaquianus S. Watson, Proc. Amer. Acad. 23: 270. 1888.— Astragalus giganteus E. Sheld. var. yaquianus (S. Watson) M. E. Jones, Rev. N.—Amer. Astragalus 234. 1923.   
 Perennial. Stems erect, decumbent to semi-prostrate, single or several, branched from base, up to 60 cm long, the trichomes of two types, 1.3–2.5 mm long, short and curly, mixed with longer and straight, these last ones spirally-twisted also, becoming ochre-ash with age. Stipules 6–17 mm long, stiff, triangular to acuminate, semi-clasping, decurrent, not connate, densely sericeous-pilose dorsally. Leaves 9–35 cm long; leaflets 17–35 oblong, 1–7.8 cm long, ovate, elliptic to narrow rhombic or elliptic, acute at both ends, sometimes abruptly acuminate distally, the midvein protruded abaxially, pilose. Peduncles 10–32 cm long, hard, ascending, rarely slightly curved; the racemes 5–21 cm long, flowers 15–67, ascending but soon deflexed. Flowers yellowish, pale yellow, green-yellowish to yellow-greenish; the calyx 7.5–14.7 × 3–5.2 mm, silky-pilose, the trichomes white; the tube campanulate or subcylindrical, 6–8.5 mm long, the teeth lanceolate, 3–6.5 mm long, papery; the banner 1.4–2.5 × 0.6–1 cm, oblanceolate, rhombic to elliptic, shallowly retuse distally; the wings 1.2–1.9 × 0.2–0.3 cm, the claw 6.9–9.6 mm long, the blade 7.5–11.4 mm long, lanceolate to oblong, obtuse distally; the keel 1.1–1.6 × 0.2–0.4 cm, the claw 7–9 mm long, the blade 5.8–7.2 mm long. Pod 1.5–2.8 × 0.8–1.3 cm, sessile, inflated, ovoid to elliptic, slightly incurved, basally rounded, distally contracted in triangular short beak, laterally somewhat compressed, sometimes dorsoventrally compressed also, dorsally flattened o slightly sulcate, ventrally openly sulcate, the valves fleshy or strongly leathery with age, glabrate, green, turning brown, ochre o black with age, thinly perpendicularly reticulate, sometimes rugose longitudinally, septum complete, the pod thence bilocular or almost so below the beak; ovules 28–47; seeds 1.9–2.6 mm long, brown to black, smooth, opaque.   
 Distribution:— Restricted to the mountains of Chihuahua. The area where this species distributes harbors at least 13 species of Astragalus, but none of them have both, yellow or light yellow flowers and leaves as large as this species. Sometimes it is locally abundant. In Mexico, restricted to the mountains in central, western and centralwestern Chihuahua (Ocampo, Yepachi, Gómez Farías, La Junta, Temósachi, Guerrero, Oscar Soto Maynez, Bachíniva, Buenaventura and Zaragoza). Also in New Mexico and Texas (USA) (Fig. 8).   
 Habitat:— Basalt, dark, yellow, clayey, sandy soils; bare slopes, deep to shallow soils; grasslands; plains with flooded grassland, overgrazed grasslands, plains with accia, prickle pear and oak; pine-juniper-madrone forest; pine forests with secondary vegetation, roadside; conifer-broadleaved forest; 1815–2600 m.   
 Specimens examined:—CHIHUAHUA: 28 August 1990, Madera—Arroyo de las Garrochas, ejido El Largo, O. Bravo B. 1303 (ANSM, CIIDIR, IEB, MEXU); 24 June 1990, Madera—Rancho La Quinta, ejido El Largo, A. Benítez 1405 (ANSM, CIIDIR, IEB, MEXU); 17 July 1997, Ocampo. 15.2 km east of Yepachic on Mex. 16, A. L. Reina 97- 783, T. R. Van Devender, D. Larson, P. Merlin, M. J. Martinez C., Dunn, Torke (CAS, MEXU, NY, TEX-LL); 19 July 1975, Collected on Hwy. 16; approximately 30 mi. W of the La Junta Jct., near mountain village, Ellis 1077, Dunn, Torke (ENCB, NY); 19 July 1975, Collected on Hwy. 16; approximately 30 mi. W of the La Junta Jct., near mountain village, Ellis 1080, Dunn, Torke (CAS, ENCB, MEXU, NY, TEX-LL); 27 August 1971, 3 mi. S of Guerrero; end of road along Rio Papigochic at dam, L. McGill 8359, D. Keil (NY); 9 September 1994, Chihuahua, Laguna de Babícora, E. Estrada 3526, T. Lebgue, G. Quintana (CAS, NY); 26 August 1994, Laguna de Babícora, 15 km al SO de San José de Babícora, C. Yen, E. Estrada 3428 (CAS, NY); 16 August 1959, between Santo Tomas and Madero, 90 miles n.w. of Chihuahua, A. R. Kruckeberg 4925, 4926 (CAS, NY); 13 May 1929, San Ysidro, S.W. of Barranca, Y. Mexia 2527 (CAS, MEXU, NY); 15 July 1997, 2 mi NE of Zaragoza on Mexico Hwy 10, N. D. Atwood 22909, J. Spencer (NY, TEX-LL); 21 October 1968, Chihuahua, near Sta.Ana Babicora on the road to Bachiniva, about 2 mi. W of the summit, R. W. Spellenberg 2004, M. Spellenberg (NY); 3 June 1908, Vicinity of Madera, E. Palmer 295 (NY, US); 17 August 1971, Temosachic, P. Tenorio 6541, C. Romero de T. (CIIDIR, IEB, MEXU, NY, US); 15 August 1994, Laguna de Babícora, E. Estrada 3229, T. Lebgue (NY); 18 September 1934, Santo Tomas, on railroad northwest of San Isidro. Sierra Madre Occidental, F. W. Pennell 18992 (US); 9 June 1971, Ignacio Zalazar, Gentry 22956, Argüelles (MEXU, US); 17 June 1997, Ocampo. 15.2 km east of Yepachic on Mex. 16, A. L. Reina 97-783, T. R. Van Devender, D. Larson, M. J. Martínez (MEXU); 14 August 1998, Mex. Hwy. 16 42 rd. km W of Basaseachi, 12.5 rd km E of Yepachi, at KM marker 307.5, R. Spellenberg 12594, L. Brouillet, T. K. Todsen (MEXU); 10 July 1958, San Pedro, in rocks along Río Papigochi, southwest of Miñaca, I. W. Knobloch 830 (ENCB); 5 August 1975, Río San Miguel, Babícora, Mpio. Zaragoza, J. M. Peña JMP-035 (ENCB).
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