Astragalus hintonii Barneby, Mem.

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

42. Astragalus hintonii Barneby, Mem. New York Bot. Gard. 13(1): 156–157. 1964

Perennial, dwarf. Stems up to 24 cm long, erect, suberect, creeping to decumbent, mostly branched, sometimes a single stem, strigose, the trichomes up to 0.4 mm long, adpressed or subadppressed, curved to straight. Stipules 1.2–7 mm long, connate (lowest), bidentate, the upper ones, also connate, but only basally or about half or a little more than it. Leaves 1–6.5 cm long, leaflets 11–27, 2–7 mm long, ovate, oblong to elliptic, retuse, or truncate and mucronate, bicolored, darker and glabrate adaxially. Peduncles up to 5.5 cm long, curved, ascending; the racemes 2–30 mm long, initially dense or almost so, soon lax, flowers 3–21, spreading to pendulous with age. Flowers purple, malva, blue-purple, yellow or light-yellow (at least in dry herbarium specimens), sometimes turining pale to brown when drying; the calyx 6.4–8.4 × 2.8–3.5 mm, strigose, trichomes black, sometimes few white ones present, the tube 3.4–4.2 mm long, campanulate, commonly purple, the teeth subulate, 1.9–4.6 mm long; the banner 1.1–1.6 × 0.5–0.9 cm, elliptic to rhombic; the wings 9–13.2 × 2.5–3.1 mm, the claw 4–5.5 mm long, the blade 6.4–9.5 mm long, oblong to obovate, lightly curved or almost straight; the keel 7.4–10.2 × 2–3 mm, the claw 3.9–5.8 mm long, the blade 4.1–5.4 mm long, obovate. Pod pendulous, stipitate (stipe 2–3 mm long), oblong to elliptic, 1–1.7 × 0.3–0.8 cm, straight or slightly curved, ventrally lightly carinate, dorsally smooth or shallowly and openly grooved, the valves papery, greenyellowish to light borwn, septum incomplete; ovules 10–16; seeds 1.2–1.8 mm long, mitten shape, light brown to olive green, shiny, the edge sometimes lighter-brown than the center.

Distribution:— Distributed in isolated localities along the Transverse Neovolcanic Mass, one in Michoacán and Estado de Mexico and the other in central Veracruz, near the border with Puebla.

Represented by two varieties, distinguished according to petals (banner) size, bracts size, and pubescence on ovary and pod.

1. Calyx teeth 2.8–4.6 mm long; the banner 11–13 mm long; bracts 3–5.5 mm long, lanceolate to elliptic; ovary and pod minute strigose; Michoacán and Estado de Mexico .................................................................................................................... var. hintonii

- Calyx teeth 1.9–2.6 mm long; the banner 14–15.6 mm long; bracts 1–2.5 mm long, ovate; ovary and pod glabrate; Veracruz ........ ....................................................................................................................................................................................... var. cofrensis