Astragalus radicans Hornem., Hort. Bot. Hafn.

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

81. Astragalus radicans Hornem., Hort. Bot. Hafn. 2: 708. 1815

TYPE:—Mexico:“Hab.F.intr.1808 sub.nom. Astr.Radicans Humb. ”. Humboldt & Bonpland s.n. Lectotype (designated here): — MEXICO, at C, C 10011808 (isolectotypes, at C, C 10011807). Grown from seed at the Botanical Garden of Copenhagen. The specimen that best matches the description was chosen [digital image! Available at https://plants.jstor.org/stable/10.5555/al.ap.specimen.c 10011807?se archUri=filter%3Dname%26so%3Dps_group_by_genus_species%2Basc%26Query%3DAstragalus%2Bradicans].

Astragalus reptans Humb. & Bonpl. ex Willd., Hort. Berol. 2: 88, Tab. 88. 1816.—“ Astragalus reptans de Humb. and Bonpl … Habitat in Mexico.” A.J.A. Bonpland s.n. (lectotype at Herbarium Willdenow in Herbarium Berlin (B), B-W 13988-010, isolectotypes (designated here):— MEXICO, at P, P00135206; P00135207; P00135208). Wrongly cited as Astragalus reptans Willd., Hortus Berolinensis 2: 88, pl. 88. 1809.

Craccina reptans (Willd.) Steven (1832: 266) .— Tragacantha reptans Kuntze (1891: 947) .— Atelophragma reptans Rydb. (1928: 159) .

Perennial. Stems up to 1 m long, prostrate, creeping, rooting in nodes, the trichomes up to 0.6 mm long, appressed. Stipules 7–12 mm long, elliptic, obovate to almost orbicular, connate, attached to the half of its length o little more, wider than stems. Leaves 10.5–30 cm long, leaflets 27–33, 18–28 mm long, oblong, elliptic, obtuse, truncate and apiculate, adaxially glabrate or sparsely so, abaxially strigose. Peduncles 7–27 cm long, erect, perpendicular to foliage growth, trichomes black; the racemes 2.5–6 cm long, flowers 20–34. Flowers yellow, cream, yellowish to ochrolecous; the calyx 7–9 × 3–3.8 mm, strigose, trichomes mainly black, the tube 4–5 mm long, campanulate, the teeth 2.5–4 mm long, lanceolate, ventral pair wider; the banner 14–15 × 5–7 mm, elliptic, oblong to oblanceolate, shallowly notched, the wings 12.5–15 × 2.2–2.7 mm, the claw 5–6 mm long, the blade 7–9.5 mm long, narrowly oblong oblique, elliptic; the keel 9–12.6 × 2.3–3.4 mm, the claw 4.4–5.6 mm long, the blade 4.2–6.5 mm long, distally oblique. Pod deflexed, subsessile or very shortly stipitate (stipe 0.4–1 mm long), oblong to elliptic, 15–22 × 5–8.3 mm, dorsoventrally compressed, basally rounded or narrowed, distally abruptly apiculate, ventrally carinate, dorsally open and shallowly sulcate, the valves rigid, papery, strigose, trichomes black or rarely also with white trichomes, mixed, septum incomplete; ovules 19–30; seeds 1.8–2.6 mm long, mitten shape, pale-brown to brown, opaque.

Distribution:— Endemic to Mexico, recorded in Mexico City and adjacent areas in the states of Mexico (Naucalpan, Ixtapaluca and Chalco) and Michoacán (Iratzio, Cerro El Águila, 19°37’N – 101°24’W) ( Fig. 23).

Comments:— The areas where A. radicans is found is also habitat for A. esperanzae , A. guatemalensis , A. hypoleucus , A. lyonnetii , A. micranthus , A. mollissimus , A. oxyrhynchus , A. strigulosus , and A. tolucanus . Of this group of species, four of them are characterized by their elliptic to oblong pods (never triquetrous), A. guatemalensis , A. radicans , A. strigulosus and A. tolucanus , and with the exception of A. radicans , none of these species produce roots at the floral nodes.

Specimens examined:— MEXICO CITY: Chapultepec , Bilimek 107 ( NYBG) ; knoll of low meadows, Valley of Mexico, 7300 ft, C. G. Pringle 6315 ( NYBG) . MICHOACÁN: Municipio Santa Clara del Cobre , Ejido Casas Blancas, 2400 m snm, J. M. Escobedo 1044 ( IEB) ; Municipio Santa Clara del Cobre , 2 km rumbo al Cerro San Miguel, J. M. Escobedo 1470 ( IEB) . STATE OF MEXICO: orilla de una milpa situada al E del sitio Arqueológico Tlapacoyan, cerca de la autopista, J. Espinoza G. s.n., ( NYBG) ; Municipio de Chalco , 2 km al S. de Tlapacoyan, 2250 m snm, Rzedowski 29055 ( ENCB) ; Municipio Chalco , 2 km al S. de Tlapacoya, 2250 m snm, Rzedowski 29055 ( ENCB) .