Astragalus tolucanus Robinson & Seaton, Porc. Amer. Acad.

Castillón, Eduardo Estrada, Quintanilla, José Ángel Villarreal, Delgado-Salinas, Alfonso & Rebman, Jon P., 2023, The genus Astragalus (Leguminosae: Papilionoideae: Galegeae) in Mexico, Phytotaxa 586 (1), pp. 1921-1935 : 1921-1935

97. Astragalus tolucanus Robinson & Seaton, Porc. Amer. Acad. 28: 104. 1893

Type: — MEXICO, Estado de Mexico, on drier ridges under pines, Nevado de Toluca , 12000 ft, 6 September 1892, C. G. Pringle 4238 (holotype: GH 00059444 digital image!; isotype: E 00383739 digital image!, E 00383738 digital image!, BR 0000005189571 digital image!, RSA 0003138 digital image!, ENCB 003334 digital image!, MEXU 01169232 digital image!, COLO 00350777 digital image!, P 00585180 digital image!, BR 0000005189908 digital image!, MU 000000141 digital image!, K 000478266 digital image!, US 00001624 digital image, NY 00005854 digital image, MEXU 01169234 digital image!, S 10-1793 digital image!, AC 00319848 digital image!, US 01014055 digital image!, RM 0002477 digital image!, MO-128355 digital image!, BM 000931696 digital image!, JE 00010699 digital image!, PUL 00000256 digital image!, G 00441208 digital image!) .

Atelophragma tolucanum (Robins. & Seaton) Rydb., Bull. Torrey Bot. Club 55: 156. 1928.

Atelophragma bracteatum Rydb., Bull. Torrey Bot. Club 55: 161. 1928.

Perennial. Stems many, up to 50 cm long, diffuse, decumbent, minute strigose, the trichomes up to 0.4 mm long, subappressed. Stipules 1.5–6 mm long, clasping and connate for a half of its length, triangular, the upper ones lanceolate little longer and connate basally only. Leaves 2–8 cm long, leaflets 13–25, 3–14 mm long, oblong, elliptic to ovate, obtuse, distally truncate or retuse, adaxially glabrate. Peduncles 2.5–11 cm long; the racemes 2–7 cm long, dense when young, lax with age, flowers 15–30. Flowers pale purple to pink-purple, blue or the banner purple veined; the calyx 6.2–9.4 × 2.3–2.8 mm, strigose, trichomes black, the tube 3.2–4.5 mm long, campanulate, the teeth 2.5–4.7 mm long, lanceolate; the banner 10–13 × 4–6 mm, oblanceolate, basally narrowed, slightly notched, recurved; the wings 9.5– 10.5 × 1.4–2.4 mm, the claw 4–5 mm long, the blade 6.2–7.7 mm long, oblanceolate, distally oblique, almost straight; the keel 7.8–8.4 × 2.2–2.6 mm, the claw 3.8–4.8 mm long, the blade 4–4.5 mm long, distally oblique, thence incurved. Pod 10–15.3 × 4–6 mm, deflexed, stipitate (stipe 2–3 mm long), oblong to elliptic, straight or almost so, narrowed at both ends, distally short cuspidate, somewhat compressed, laterally rounded, dorsally wide sulcate, the valves thin, glabrate or strigose, the trichomes black, turning papery and brown with age, reticulate, septum incomplete; ovules 5–14; seeds 2–2.4 mm long, mitten shaped, brown, smooth.

Distribution:— Endemic to Mexico, central region of Mexico, in the State of Mexico (Nevado de Toluca, Sultepec, Temsacaltepec, and Santiago Tlazala), also in Hidalgo (Epazoyucan) ( Fig. 27 ).

Habitat:— Oak scrubland; fir forest; cleared pine forest, associated with short dense grassland; cold pine forest; 2750–3910 m

Comments:— Undoubtedly, this species forms part of a species complex together with A. guatemalensis , A. hidalgensis and A. strigulosus , which are characterized by their clasping and connate stipules, stipitate, oblong to elliptic, widened, never triquetrous or inflated bladdery pods. Of these species, A. strigulosus is distinguished by its white petals; A. hidalgensis (both varieties) has small petals, never larger than 7.8 mm long, A. tolucanus and A. guatemalensis var. brevidentatus are physiognomically very similar to each other, but A. g. var. brevidentatus has both, the calyx (3.2–6 mm) and its sepal teeth (0.6–2.5 mm) shorter, and relatively larger pods (21 mm long).

Specimens examined:—HIDALGO: 21 July 1988, Cuyamaloya , 3 km al NNW de Matías Rodríguez, Mpio. De Singuilucan, M. Medina C. 3676, M. A. Barrios ( IEB) ; 29 July 1938, El Chico, E. Lyonnet 2208 ( MEXU, US) ; 4 August 1963, 6 km al W de Real del Monte, Rzedowski 17040 ( ENCB) ; 24 August 1972, 1 km al S de EL Guajolote, Mpio. Epazoyucan, Rzedowski 29209 ( ENCB) ; 16 August 1975, 0.5 km después del crucero a EL Chico, Crucero Real del Monte , I. García G. 285 ( ENCB) ; 22 June 1975, alrededores del cerro Las Ventanas , Mpio. El Chico, Rzedowski 33280 ( ENCB) ; 3 August 1975, 2 km all SW de EL Guajolote , Mpio. Epazoyucan, M. Medina C. 567 ( ENCB) ; 19 June 1976, 1 km al SSW de Las Ventanas, Mpio. El Chico , M. Medina C. 1434 ( ENCB) ; 12 August 1971, 4 km all W de Real del Monte, Rzedowski 28437 ( ENCB) . MEXICO CITY: 20 October 2010, J. L. Díaz s.n. ( MEXU) ; VIII September 1930, Federal District: Peña de Los Charros , P. G. Rusell 144, M. J. Souviron ( US) ; 2 August 2002, Cerro Nepanapa por la terracería que va a cabaña Pelagatos. Área Natural Protegida: Nepanapa. Delegación Milpa Alta, F. César G. 372 ( MEXU) ; 11 August 1957, Entre Las Palmas y San Miguel, Sierra de Las Cruces , L. Paray 2406 ( ENCB) . MICHOACÁN: 14 August 2015, Ocampo, D. Álvarez 15927 ( MEXU) . MORELOS: 9 August 1964, J. Arvizu 44 ( MEXU) . STATE OF MEXICO: 20 August 1943, Trans-Mexican Volcanic Belt. In open woods of Pinus , western side of Nevado de Toluca, 3 km. southeast of San Juan , R. T. Clausen 6019, R. C. Godinez ( ENCB, NY, TEX-LL, US) ; 6 October 1932, Mesón Viejo, G. B. Hinton 1900 ( MEXU, NY, US) ; 6 September 1892, C. G. Pringle 4238 ( MEXU, NY) ; IX-1937, Cerro Cabeza ( Estado de Mexico ), E. Lyonnet 1616 ( US) ; 12 July 1938, Nevada de Toluca, Mex. , 3536 m, E. K. Balls 5023 ( US) ; 26 April 2015, Nevado de Toluca, 3.8 km después de la caseta del parquet Los Venados , subiendo por el camino hacia los lagos del crater, Y. Ramírez A., V. W. Steinmann 2361 ( IEB) ; 23 August 1947, F. A. Barkley, G. L. Webster, B. L. Westlund 82 ( MEXU) ; 20 August 1943, Western side of Nevado de Toluca 3 kn southeast of San Juan , R. T. Calusen 6019 ( MEXU) ; 2 October 2001, Metepec — Ferrocarril Toluca-México, paralelo al paseo Tollocán , a la altura de Chrysler y de la salida a Metepec, H. Vibrans 7537 ( MEXU) ; 10 June 1932, Mesón Viejo, G. B. Hinton 1900 ( MEXU) ; 6 September 1958, Nevado de Toluca; northwest side of mtn, J. H. Beaman 2481 ( MEXU) ; 19 August 1971, Alrededores de la Presa Iturbide, Mpio. Iturbiude (Santiago Tlazala), Rzedowski 28560 ( ENCB) ; 18 July 1968, Plaomas, Mpio. Iturbide (Santiago Tlazala), Rzedowski 25902 ( ENCB) ; 7 August 1977, Alrededores de la Presa Iturbide , 6 km al WNW de Santiago Tlazala, Rzedowski 35108 ( ENCB) ; 6 July 1968, Alrededores de la Ranchería El Capulín , Mpio. Tescaltitlán, D. García S. 234 ( ENCB) ; 4 August 1962, Nevado de Toluca, Rzedowski 15772 ( ENCB) ; 14 August 1964, Nevado de Toluca, L. González Q. s.n. ( ENCB) ; 16 July 1965, NW slopes of Nevado de Toluca, 10 km (by road) SW of jct of roads to Sultepec and Temascaltepec on Hwy 130 to Temascaltepec or 27 km (by road) SW of Toluca, K. Roe 264, E. Roe, S. Mori ( ENCB) ; 4 August 1962, L. Huerta M. s.n. ( ENCB) .

Figures

FIGURE 27. Map showing the distribution of Astragalus tolucanus, A. trichopodus var. lonchus, A. vaccarum, and A. waterfallii in Mexico.