Astragalus hartmanii Rydb.

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

38. Astragalus hartmanii Rydb. , in N. Amer. Fl. 24: 442. 1929

Type:— MEXICO, Chihuahua, Near San Diego ranch, alt. 6000 ft., 2 May 1891, Hartman 678 (holotype: NY00005800 !, isotype: PH 00005434 digital image!, GH00059416, GH00059417 digital images!, US 00004128 digital image!,

Perennial. Stems up to 48 cm long, strong, soflty pilose, trichomes up to 5 mm long, curly, straight and ascending, turning tan or ochre or with rust tones with age. Stipules 7–20 mm long, free, lanceolate to deltoid. Leaves 7–25 cm long; leaflets 21–29, 8–58 mm long, elliptic, ovate, rhombic to oblanceolate, acute to obtuse, thin texture, glabrate or almost so adaxially. Peduncles 12–25 cm long, hard, striate; the racemes up to 10.8 cm long, flowers 15–25 narrow, long and ascending. Flowers yellow to yellow-lemon; the calyx 28–30 × 6–7 mm, softly pilose, the tube 16–17 mm long, cylindrical, distally constricted; the teeth 11–12 mm long, linear to lanceolate; the banner 32–37 × 11 mm, oblanceolate, obcordate or almost so; the wings 31–34 × 3.3 mm, the claw 20–22 mm long, the blade 13–14 mm long, narrow oblanceolates; the keel 30–32 × 3.9–4.3 mm, the claw, 19–22 mm long, the blade 11–14 mm long, semi-obovate, incurved. Pod 15–35 x 12–20 mm, sessile, humistrate with age, ovoid to oblong, inflated bladder-like, dorsoventrally compressed, laterally rounded, the lateral faces rounded, basally rounded, and distally contracted in a short triangular beak, shallowly sulcate dorsally, the valves green, 1 mm wide when fresh**, turning rigid and leathery, internally pubescent, ochre, smoothly reticulate and wrinkled, black and stiff-papery, septum complete, at least below the peak, thence the pod bilocular; ovules 40–46; seeds 2.7–2.8 mm long, brown-black, mitt-shaped, smooth.

Distribution:— Endemic to northwest Mexico. Only in in the state of Chihuahua (Colonia Juárez, Ignacio Zaragoza, El Huili, Valle Grande, San José de Los Pozos, Pacheco, El Gavilán) ( Fig. 11 ).

Habitat:— Flood plains; abundant in tickets along the riverside, associated with riparian disturbed vegetation; associated with poplar, sycamore, ash tree, walnut, willow; also in oak-pine-sumac forest; 1560–1880 m.

Comments:— From the approximately 10 species distributed in those areas, at least three of them can be separated by their yellow petals, A. giganteus , A. hartmanii and A. longissimus , however, only the first two species have sessile and inflated pods. Astragalus giganteus has semi-clasping stipules, the racemes up to 20 cm long with 15–65 flowers, the calyx 7.5–14.7 mm long, smaller petals (banner 1.4–2.5 cm long, wings 1.2–1.9 cm long, the keel 1.1–1.5 cm long), and shorter, non-humistrate pods 1.5–2.5 cm long. *(Spellenerg, 1988).

Specimens examined:— CHIHUAHUA: 8 June 1987, On the flood plain of the Rio Piedras Verdes 5 km NW of Colonia Juarez, ca. 20 air km SW of Casas Grandes , R. Spellenberg 9163 ( MEXU, NY) ; 9 June 1987, Ca. 60 air km SW of Casas Grandes, on the flood plain at the crossing of the Rio Piedras Verdes and on steep wooded 50% 5 km SE of El Huili, R. Spellenberg 9178 ( ENCB, MEXU, NY) ; 5 April 1997, Juarez River ( Piedras Verdes ) 0.5 mi. w. of Juarez, N. D. Atwood 21625, 21630 ( NY) ; 2 May 1891, Near St. [San] Diego ranch. AAlt. 6000 ft., C. V. Hartman 678 ( NY) .

Figures

FIGURE 11. Map showing the distribution of Astragalus hartmanii, A. hartwegii, A. helleri, A. hidalgensis var. hidalgensis, and A. hidalgensis var. protensus in Mexico.