37. Astragalus harshbergeri (Rydb.) A. E. Estrada, Villarreal & A. Delgado. Phytotaxa 470(2): 127–130

Astragalus radicans Hornem. var. harshbergeri Barneby, Mem. New York Botanical Garden 13: 165. 1964.

Basionym: Atelophragma harshbergeri Rydb. Bull. Torr. Club 55: 160. 1928.

TYPE:— MEXICO. Mexico City, Salazar, Sierra de Las Cruces, alt. 11000 ft. 13 Aug 1896, J. W. Harshberger 20 (holotype: GH!; isotypes: PH00005764 digital image!; PH00005765 digital image!; US 00004129 digital image!).

Plant perennial. Stems up to 80 cm long, and 30 cm tall, prostrate, creeping, commonly rooting at the nodes, the trichomes up to 0.6 mm long, appressed. Stipules 3–5.5 mm long, elliptic, obovate to almost orbicular, connate, attached half of its length or little more, much wider than stems. Leaves up to 10 cm long, leaflets 17–26, 4–12 mm long, lanceolate, oblong, elliptic, obtuse, truncate and apiculate, adaxially glabrate or sparsely so, abaxially strigose. Peduncles 2–7 cm long, erect, perpendicular to foliage growth, trichomes black; the racemes short, 1–2.5 cm long, flowers 5–12. Flower bracts oblong to ovate-oblong, 2–5 × 1–1.5 mm long. Flowers yellow, cream, yellowish to ochrolecous; the calyx 5.5–8.9 × 2.7–3.6 mm, strigose, trichomes mainly black, the tube 3–6 mm long, campanulate, the teeth 2–3.5 mm long, lanceolate, ventral pair wider; the banner 11.5–13 (very rarely up to 15 mm) × 4–6 mm, elliptic, oblong to oblanceolate, shallowly notched, the wings 11–12 × 2–2.5 mm, the claw 5–6.5 mm long, the blade 5.5–7.3 mm long, narrowly oblong oblique, elliptic; the keel 8–10 × 2.1–3 mm, the claw 4–4.5 mm long, the blade 4–6 mm long, distally oblique; androecium diadelphous, stamens 10, 8.5–9 mm long, anthers yellow, 0.5 mm long; gynoecium 9 mm long, ovary 4.5 mm long, oblong, glabrate, style linear, 4.5–5 mm long, stigma minute. Pod deflexed, subsessile or very shortly stipitate (stipe 0.4–1 mm long), oblong to elliptic, 15–21 × 5–8.2 mm, somewhat 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 trichomes white or mixed, septum incomplete; ovules 14–24; seeds 1.8–2.6 mm long, mitten shaped, pale-brown to brown, opaque.

Distribution:— Restricted to the state of Mexico and Mexico City in high altitudes, 2600–3300 m. Salazar, Sierra de Las Cruces, adjacent to Cerro El Ajusco, in close proximity to Naucalpan (Villa Alpina), Ixtapaluca, Llano Pinahua, 10 km al S del Llano Grande (Fig. 10).

Habitat:— Rare; cold pine forest; conifer forest; 2600–3300 m.

Comments:— One of two species in Mexico that roots at its flowering nodes.

Additional specimens examined: MEXICO CITY: Delegación Ixtapalapa, 2 km al E de Ixtapalapa, cerca de la estación XEW, Rzedowski 20088 (ENCB). STATE OF MEXICO: not locality, L. W. Boege 290 (MEXU); near Río Frío at Llano Grande, A. J. Sharp 4485 (MEXU); Ixtapaluca, Estación Experimental Forestal de Zoquiapan, M. C. Obieta 40 (MEXU); Municipio Ixtapaluca, Estación Experimental de Investigación y Enseñanza de Zoquiapan, 8 km al sur de Río Frío, casi 200 m al N de Aculco, sobre camino seis,, R. Vega A. 196 (ENCB); Municipio Ixtapaluca, Llano Pinahua, 10 km al sur de Llano Grande, Rzedowski 36796 (IEB, MEXU); Llanos de Salazar, F. Medellin, G.C. Rzedowski s.n. (ENCB); Municipio Lerma, Parque Nacional Miguel Hidalgo y Costilla (La Marquesa), llanos, camino a Chalma, Sánchez-León 66 (ENCB); Municipio Ixtapaluca, Estación Experimental y de Investigación y Enseñanza de Zoquiapan, 8 km al sur de Río Frío, Llano Xaxalpa, orilla de camino 5, pie del Cerro El Papayo, R. Vega A. 381 (ENCB); Municipio Tlalmanalco, Llano Atlihuiyán, 10 km al E de San Rafael, Rzedowski 37875 (IEB); Municipio Chalco, 1 km al N. de Llano Grande, en las faldas del el Cerro El Telapón, Rzedowski 18438 (ENCB); Municipio Zoquiapan, Llano Grande, cerca de Río Frío, R. Cruz C. 1268 (ENCB); Municipio Ixtapaluca, Llano Tepochaico, 10 km al sur de Río Grande, Rzedowski 36807 (ENCB); Municipio Naucalpan, Villa Alpina, Rzedowski 36323 (ENCB).