Astragalus mario-sousae A. E. Estrada, A. Villarreal & C. Yen

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

56. Astragalus mario-sousae A. E. Estrada, A. Villarreal & C. Yen , Brittonia 57(4): 314. 2005

Type:— MEXICO, Nuevo León, Municipio Santa Catarina, El Jonuco , 13 June 2001, E. Estrada 12729, & C. Yen (holotype: MEXU01196762 !; isotype: ANSM083411 !, NY00888059 !) .

Perennial. Stems up to 54 cm long, diffuse, ascending, suberect or sometimes erect, appressed to villous, the trichomes up to 1 mm long, appressed, of two types, ones short and mixed with straight, or slightly longer curved ones. Stipules 1.5–2.3 mm long, clasping, connate at least basally, the upper ones clasping only in the base by a tenuous horizontal line. Leaves 1.2–4.2 cm long, leaflets 15–21, 2.1–8.2 mm long, elliptic to obovate, pilose in both surfaces, denser abaxially. Peduncles 1.1–6.9 cm long, erect or slightly curved; the racemes 2–20 mm long, flowers 4–11. Flowers purple or purple with white tones; the calyx 4.6–5.1 × 2–2.3 mm, strigose, pale green, trichomes white, 0.1–0.15 mm long, black, the tube 3.2–3.5 mm long, the teeth 1.2–1.5 mm long, triangular to lanceolate; the banner 9.6–10.1 × 5.2–5.4 mm, obovate, slightly retuse; the wings 8.2–8.4 × 2.2–2.6 mm, the claw 3.2–3.6 mm long, the blade 5–5.3 mm long; the keel 6–6.5 × 1.6–2 mm, the claw 3.3–3.5 mm long, the blade 3.2–3.3 mm long. Pod 10–11 × 3.1–3.8 mm, sessile, ascending, oblong, slightly incurved, triquetrous, compressed, ventrally carinate, laterally angles rounded, dorsally widely grooved, basally widely rounded to truncate, distally narrowing abruptly in a short beak, 1–1.9 mm long, the valves stiffly papery, white-strigose, smoothly reticulate, ochre or turning brown to dark-brown with age, septum complete, the pod thence bilocular; ovules 9–11; seeds 2.5–3 mm long, mitten shaped, brown to dark-brown, smooth.

Distribution:— Endemic to Mexico, in Nuevo León (El Jonuco, Santa Catarina municipality) ( Fig. 17 ).

Habitat:— Inhabiting oak-forest; 1800–2000 m.

Comments:— The arid lands in the political border between Coahuila and Nuevo León harbor about 11 species of Astragalus , however, only A. emoryanus , A. greggii , A. mario-sousae , and A. nuttallianus have triquetrous oblong pods. A. greggii is the only species with retrorse pubescence. From the other three ones, A. mario-sousae is the only one with a perennial habit.

Specimens examined:— NUEVO LEÓN: 13 June 2001, El Jonuco, E. Estrada 12729, C. Yen ; 5 November 2017, El Jonuco, Mpio. Santa Catarina, P. Garza-Zambrano 101, E. Estrada ( CFNL, MEXU) .

Figures

FIGURE 17. Map showing the distribution of Astragalus mario-sousae, A. martinii, A. micranthus var. micranthus, and A. micranthus var. seatoni in Mexico.