Astragalus mollissimus Torr., Ann. Lyceum Nat. Hist.

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

59. Astragalus mollissimus Torr., Ann. Lyceum Nat. Hist. New York 2(6): 178 (–179). 1827

Perennial. Stems short, up to 23 cm long, when abundant, the external ones diffuse and prostrate, the central ones ascending or decumbent, always shorter than longer leaves, sometimes acualescent, densely or soflty (with age) pilose, the trichomes 0.4–2 mm long, two types, ones short and curled, the longer ones ascending to extended, straight to sinuous, and always spirally-curled, both types turning rusty to yellowish with age. Stipules 2.7–17 mm long, semiclasping, not connate, lanceolate, triangular to caudate. Leaves 3–26 cm long, leaflets 11–35, 3–47 mm long, ovate, oblong-obovate, obovate to orbicular, coarse and hard, of similar size or the distal ones, gradually decreasing in size. Peduncles 1–25 cm long, at the bigining ascending, but prostrate or reclinate (by the weight of the developed fruits) with age; the racemes 1–17 cm long, short and dense when young, but increasing in size with age, flowers 7–45. Flowers white-cream, purple, rose-purple, rose-lavander, yellowish with lilac tones, turning bronze with age; the calyx 6.8–14 × 3.4–7 mm, strigose to villous, white, rarely mixed con black trichomes, the tube 4–9.5 mm long, campanulate to cylindrical, usually contracted distally, gibbous, the teeth 1.7–5.6 mm long, lanceolate to linear-setaceous; the banner 11.8–24.5 mm long, widely oblanceolate, basally narrow, subentire to reniform apically; the wings 11.5–24 mm long, narrow oblong, incurved; the keel 0.9–2.45 × 0.4–1.3 cm, semi-obovate, incurved. Pod sessile, ascending, frequently humistrate with age, oblong, elliptic, lunate, ovate, turgid, widened, somewhat inflates, but not bladderlike, obcompressed, basally rounded or truncate, distally contracted in a short conic beak, slightly sulcate along both sutures, straight to incurved, the valves fleshy, hard, stiffy to rigid papery, rugose, reticulate, glabrate, strigose to villous, septum complete, the pod thence bilocular; ovules 20–31; seeds 2–2.8 mm long, mitten shaped, purple brown, dark-orange, olive, sometimes black or with purple tones, opaque.

Distribution:— Species with a wide distribution in Mexico, from Chihuahua, northwestern Durango to the northeastern, in the arid region of Nuevo León, to Mexico City and Veracruz.

Three varieties distributed in Mexico ( Barneby, 1964). Mainly diferentiated by the pubsecence size on fruit, fruit size and, chamber numbers in the beak.

1. Trichomes of pod shorter than 1 mm long .......................................................................................................................... var. eralei

- Trichomes of pod longer than 1 mm long (if shorter than 1 mm, the beak of the pod unilocular .....................................................2

2. Pod ovoid, beak unilocular .................................................................................................................................... A. m. var. irolanus

- Pod narrow-oblong to lanceolate-elliptic, beak bilocular..................................................................................... A. m. var. bigelovii