Astragalus circumdatus Greene, Pittonia, 1888

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

11. Astragalus circumdatus Greene, Pittonia 1: 173. 1888

Type:— Mexico, Baja California, Hanson’s Ranch, San Rafael Moiuntains , Lower California , May 1888, Lemmon s.n. (Holotype: 26902 NDG digital image!; isotype UC 82570 digital image!).

Perennial, dwarf. Stems very short, up to 23 cm long (Thorne 55817, MEXU), prostrate, or the tips slightly ascending, the basal nodes very short, and without leaves, strigose, the trichomes, somewhat appressed or ascendant, up to 0.5 mm long. Stipules 1–2 mm long, ovate, acute, the lowest clasping, wider than stem, forming a broad loose sheath, the upper ones, amplexicual, basally attached or connate and attached to the middle of its length. Leaves 1.2–3.5 cm long, leaflets 13–17, 1–5 mm long, eliptic to obovate, obtuse to retuse, glabrate adaxially. Peduncles 0.5–1.5 cm long, tilted down due to the weight of ripe fruits, thence those humistrate; the racemes 0.4–1 cm long; flowers 3–15, loose, ascendant or slightly spreading. Flowers *white, whitish, greenish-white, **cream, ***pale green to 1 purple; the calyx 4.2–6.2 × 2.3–2.8 mm, campanulate, papery, strigulose, the teeth 1.5–2.5 mm long, subulate; the banner 7.3–10 × 5–7 mm, ovate, widely retuse; the wings 7–9.3 × 1.4–2 mm, linear-obovate to linear-oblong, the claw 2.8–3.8 mm long, the blade 4.5–6.4 mm long, apex obtuse; the keel incurved, 6.9–8.8 × 2–2.4 mm, the claw 2.8–4 mm long, the blade 4.6–5.5 mm long, triangular at apex. Pod sessile, 10–16 × 4–5.5 mm, ascendant, humistrate, caducous, oblong-elliptic, elliptic to obovate, narrow at base, abruptly contracted at apex, subcylindrical, laterally compressed but somewhat convex, the sutures evident, the valves strigose, fleshy to leathery, brown to dark brown to brown-black, septum incomplete, 1–1.3 mm wide, the pod almost bilocular, sometimes more o less concealed by leaves; ovules 18–21; seeds 2–2.5 mm long, light brown, opaque.

Distribution:— Endemic to Baja California in the Sierras Juárez and San Pedro Mártir ( Fig. 3 ).

Habitat:— Sandy, gravelly and granitic soils; meadows and sandy and gravelly meadows; along streams; shallow slope; open grassland; overgrazing grasslands and streams; grazed meadows in full sun; pine-aspen woodland; coniferous forest with; associations of oak-shrubs-grasses; 1700–2590 m.

Comments:— Species characteristic for its small size, adjacent basal internodes without leaves, short peduncles and oblong-obovoid, humistrate pod.

Specimens examined:—BAJA CALIFORNIA: 26 June 1893, San Pedro Martir , T. S. Brandegee s.n. ( NY, CAS) ; 18 June 1985, Sierra San Pedro, Martir, Vallecitos : near road to Observatory and camp-ground, R. F. Thorne 60839, R. Dahlgren, S. Boyd, D. Charlton ( NY) ; 7 May 1986, Sierra San Pedro Martir: near road to Observatorio , open, sandy, dry meadow at Vallecitos, R. F. Thorne 61951, T. S. Elias, P. Rojas ( MEXU, NY) ; 25 May 1975, Sierra Juárez. 3 miles SE of San Pedro Martir, R. Moran 22050 ( ENCB, NY, SD) ; 2 June 1968, Sierra San Pedro Martir , R. Moran 15075 ( CAS, MEXU, NY, SD) , 15084 (CAS, SD, NY); 18 June 1971, Sierra San Pedro Martir;2.0 miles west of Vallecitos. , I. L. Wiggins 21461 ( ENCB, NY) ; 18 May 1972, La Encantada Meadow, San Pedro Martir National Park , E. McMillan s.n. ( CAS) ; 17 June 1971, Near north end of Vallecitos Meadow 1mile south of road to Observatory, Sierra San Pedro Mártir , I. L. Wiggins 21448 ( CAS, ENCB) ; 2 July 1973, Sierra San Pedro, Martir. Locally common in dry gravelly meadow west of Los Llanitos , R. Moran 21081 ( SD, MEXU, US) ; 2 July 1982, Sierra San Pedro Martir ; near summit of Cerro de la Cupula, R. Moran 30983 ( SD) ; 30 May 1977, Sierra San Pedro Martir ; above Yerba Buena, R. Moran 24204 ( SD) ; 11 August 1977, Sierra San Pedro Martir ; Rancho Viejo, R. Moran 24490 ( SD) ; 3 July 1972, Sierra San Pedro Martir ; La Grulla, R. Moran 19170 ( SD, TEX-LL) ; 16 August 1967, Sierra San Pedro Martir ; Yerba Buena, R. Moran, R.F. Thorne 14238 ( ENCB, SD) ; 24 June 1991, Sierra San Pedro Martir ; Vallecitos, D. Clemons, C. Brey 2320, 2321 ( SD) ; 16 June 1933, Laguna Hansen, F. F. Gander 2631 ( SD) ; 19 August 1967, Sierra San Pedro Martir ; La Encantada, R. Moran 14380 ( SD) ; 24 May 1992, Sierra Juarez; just north of Valle Redondo , R. Moran 31082 ( SD) ; 28 June 1998, Sierra San Pedro Martir, south of Vallecitos near Cerro la Botella Azul , J. Rebman 5406 ( SD) ; 8 June 1997, Parque Nacionale Sierra San Pedro Martir, Vallecitos meadow, extreme western margin, J. M. Porter 11488, L. E. Machen ( SD) ; 9 June 2016, Sierra de San Pedro Martir : lower southwestern end of Santa Rosa meadow, J. Rebman 31736, S. Vanderplank, A. Peralta, A. Harper ( SD) .

Figures

FIGURE 3. Map showing the distribution of Astragalus arizonicus, A. brauntonii var. lativexillum, A. brazoensis, A. carminis, A. cenorrhynchus, and A. circumdatus in Mexico.