Astragalus pennellianus Barneby,

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

69. Astragalus pennellianus Barneby, Mem. New York Bot. Gard. 13: 170. 1964

Type: — MEXICO, Durango, east slopes of Cerro Prieto, about 20 miles airline w of Otinapa , 10 July 1950, J. H. Maysilles 7354 (holotype: MICH1107118 digital image!; isotype NU00005827 !) .

Perennial. Stems up to 40 cm long, decumbent to suberect, single or branched from base, strigose to villous, trichomes up to 0.9 mm long, sub-appressed to incumbent. Stipules 1–7.5 mm long, clasping and connate, papery, glabrate, forming a bidentate sheath around the stem´s circumference or those, single and acute apically (upper ones). Leaves 2–7.5 cm long, leaflets 15–47, 1–5.5 mm long, gradually decreasing the size of the base towards the apex, oblong, elliptic, ovate to obovate, wide notched, adaxially glabrate, abaxially densely pubescent along midvein. Peduncles 4.5–9 cm long, straight or pronouncedly curved; the racemes 2–4 cm long, flowers 7–25. Flowers purple, white to cream or pale-purple, deflexed with age; the calyx 4.7–6 × 2–2.7 mm, villous, the trichomes white short and long, others short ochre, the tube 3.9– 3.8 mm long; the teeth 1.7–2.5 mm long, lanceolate to subulate; the banner 8–9.3 × 4–5 mm, recurved, elliptic to obovate, wide retuse; the wings 7.5–9.6 × 1.8–2.2 mm, the claw 3–3.8 mm long, the blade 5.5–6.6 mm long, elliptic to oblanceolate, oblique, incurved; the keel 6–7 × 2–2.3 mm, the claw 3–3.5 mm long, the blade 3.3–3.9 mm long, almost obovate. Pod deflexed, stipitate (stipe 3.5–7 mm long) obcompressed, lanceolate, oblong to elliptic, 16–28 × 5–6.2 mm, straight or slightly curved, basally narrow, distally ending in a short to long triangular to cuspidate beak, ventrally carinate, dorsally wide and openly sulcate, the valves glabrate, green, turning brown or sometimes purple with age, papery, slightly reticulate, septum complete, the pod thence bilocular or almost so; ovules 10–14; seeds 1.9–2.3 mm long, mitten shape, brown to purple.

Distribution:— Endemic to Mexico, exclusively from Durango, at central (Durango and Pánuco de Coronado), southwestern (Pueblo Nuevo) and southern end (Mezquital) Durango ( Fig. 21 ).

Habitat:— Mountians; cold conifer forest; oak-pine forest; oak forest; grasslands associated with pine, juniper, oak, and madrone; associations of douglas fir - spruce - fir - oak, roadside; 2620–3100 m.

Comments:— The south region of Durango harbors eight species of Astragalus . Four of them has white flowers (with some shade of purple, pink or violet), purple to bluish; A. goldmanii , A. hartwegii , A. pennellianus and A. potosinus . The first two has triquetrous pods, although sometimes semi-ovate, but evidently triquetrous. A. pennellianus and A. potosinus are characterized by their oblong, elliptic, lanceolate (never triquetrous) stipitate pods, but, A. potosinus has ovary and pod pubescent.

Specimens examined:— DURANGO: 12 September 1982, 17 km al SE de El Salto , S. González 2068 ( IEB), 2068-a ( CIIDIR); 21 July 1985, 5 km de Charcos, camino a la Guajolota, Mezquital, Durango, M. González 1800 ( CIIDIR); 8 October 2010, C. Vázquez R. s.n., N. B. Cabada A. ( CIIDIR); 27 June 1992, Pueblo Nuevo, Durango, S. González 5270 (ANSM, CIIDIR, ENCB, MEXU) ; 15 July 1990, A. García 4562, S. González ( ANSM, CIIDIR, MEXU) ; 21 July 1985, 6 km de los Charcos , camino a la Escondida, Mezquital, Durango, M. González 1779, et al ( CIIDIR) ; 24 August 1957, Ca. 25 mi. W of Durango on road to El Salto, O. T. Solbrig 4616, R. Ornduff ( NY) ; 24 August 1986, Just S of Puerto Buenas Aires along Mexican Hwy 40 between Mazatlan and Durango, D. E. Breedlove 63019, B. Anderson ( NY) ; 29–30 August 1934, Metates , north of Cueva, F. W. Pennell 18399 ( NY, US) ; 13 August 1959, 17 miles southwest of El Salto , U. T. Waterfall 15488 ( MEXU, NY) ; 26 July 1972, Along Rte 40, 4.8 mi W of Los Mimbres, L. McGill 9466, R. Brown, D. J. Pinkava ( NY) ; 18 October 1965, Near crest of Sierra Madre, 20 miles west of El Salto, H. D. Ripley 14186, R. C. Barneby ( NY, US) ; 10 July 1950, E slopes of Cerro Prieto (about 20 airmiles W of Otinapa). Alt. 3000–3100, J. H. Maysilles 7354, R. Brown, D. J. Pinkava ( NY) ; VI-1984, Pueblo Nuevo, Ej. San Pablo, L. Martínez M. 529 ( MEXU) ; 3 July 1982, 4.5 km, al SW de El Salto , Brecha El Salto-Pueblo Nuevo, P. Tenorio L 800, C. Roero de T. ( MEXU) ; 26 June 1992, Pueblo Nuevo , Durango, S. González 5270 ( MEXU) .

Figures

FIGURE 21. Map showing the distribution of Astragalus palmeri, A. parvus, A. pennellianus, A. pilosior, and A. piscinus in Mexico.