Astragalus tephrodes A. Gray var. tephrodes

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

93. Astragalus tephrodes A. Gray var. tephrodes

Type:— USA, New Mexico, plains at the base of the Organ Mountains , 30 April 1852, C. Wright s.n. (holotype: GH 00058959 digital image!) .

Astragalus tephrodes A. Gray , Smithsonian Contr. Knowl. 5(6): 45. 1853. — Tragacantha tephrodes (A. Gray) Kuntze , Revis. Gen. Pl. 2: 948. 1891. — Xylophacos tephrodes (A. Gray) Rydb. , Bull. Torrey Bot. Club 52: 147, 156. 1925. — A. tephrodes A. Gray var. typicus, Amer. Midl. Nat. 37: 465. 1847.

Perennial. Stems short and shorter than largest leaves, up to 15 cm long, or acaulescent, prostrate with age, pubescent, pilose, the trichomes up to 0.8 mm long. Stipules up to 2.5 cm long, trichomes 0.4–0.7 mm long, appressed o incurved; Stipules 2–7.2 mm long, lanceolate to ovate. Leaves 4.5–19 cm long, leaflets 11–31, 3–17 mm long, elliptic to oblanceolate, retuse or subacute, adaxially glabrate to sublgabrate adjacent to midvein. Peduncles 4–17 cm long, incurved, ascending, erect when young, recurved to prostrate with age; the racemes 2–8.5 cm long, lax, flowers 10–20. Flowers pink, purple, lilac, white with purple tones, sometimes turning bluish when drying; the calyx 4.8–9.2 × 3.2–4 mm, minute pilose, trichomes up to 0.7 mm long, white or black and white mixed, straight, the tube 4.5–7 mm long, cylindrical or campanulate, sometimes with purple tones, the teeth 1.2–2.3 mm long, subulate to triangular; the banner 10.7–17.5 × 6.7–8 mm, obovate, to rhombic or elliptic, shallowly retuse; the wings 11.8–17.5 × 2.3–3.2 mm, the claw 4.2–9 mm long, the blade 7.2–9 mm long, lanceolate to oblong, distally oblique; the keel 9.2–14.7 × 2.9–3.8 mm, the claw 4.5–12 mm long, the blade 5.6–8 mm long, apically oblique, lunate to elliptic. Pod ascendant, humistrate with age or soon, 10–23 × 5–8 mm, sessile, oblique, ovoid, distally acuminate, somewhat compressed, dorsally flattened or somewhat convex, ventrally strongly carinate, basally, rounded to truncate, distally contracted in a triangular to long acuminate 3–6 mm long beak, the valves somewhat leathery, somewhat rigid, densely pilose, septum absent; ovules 24–45; seeds 1.8–2.2 mm long, mitten shaped, brown or dark-brown, opaque.

Distribution:— In Mexico, recorded only in extreme northern Chihuahua, in close proximity to the USA border. Also, in New Mexico and Arizona ( USA) ( Fig. 26 ).

Habitat:— Arid scrublands, desert areas; 1400–1700 m.

Comments:— Description of this species was made from specimens near the border with Mexico (15-IV-1995, R. D. Worthington 24628 (NY); 5-IV-1970, R. Spellenberg 2231 (NY). This arid zone of northwestern Mexico along with New Mexico and Arizona concentrate several species such as A. allochrous , A. cobrensis var. maguirei , A. humistratus var. sonorae , A. lentiginosus var. borreganus , A. mollissimus var. bigelovii , A. nothoxys , A. nuttallianus var. austrinus , A. thurberi and A. wootonii var. wootonii . But only three of the species ( A. cobrensis var. maguirei , A. mollissimus var. bigelovi and A. tephrodes ) have widened lanceolate, elliptic, oblong, obovoid or clavate-elliptic pods, never triquetrous or inflated like a bladder. Astragalus mollissimus var. irolanus is easily discerned by its long calyx (10.5–13.5 mm long), and A. cobrensis var. maguirei has short petals, never longer than 8 mm long.

Specimens examined:—CHIHUHAHUA: not date, Mexican Boundary Survey, Valley of the Rio Grande , below Doñana, C.C. Parry, three samples, s.n. (code bars 0128 3327), 260 & 265, C. Wright, A. Schott. ( NY). NEW MEXICO (Very near to the Mexican border): 20 April 1973 , Luna Co., U.S. Highway 70–80, 7.4 miles west of Dona Ana County line, N. H. Holmgren 6897 ( NY); 20 April 1973 , Luna Co., Florida Mountains, 14 airline miles southwest of Deming , N. H. Holmgren 6887 ( NY); 15 April 1995 , Luna Co., Cedar Mts. , about 10 air mi. ENE of Hachita, 1 mi N of the Williams Ranch in low area of mts. where graded road crosses and passes N to Gage, R. D. Worthington 24628 ( NY); 17 May 1992 , Dona Ana Co., Approx. 2 air miles south-southeast from top of Bishop Cap along Santana Road in small community east of Vado , R. D. Worthington 20873 ( NY); 8 April 1989 .

Figures

FIGURE 26. Map showing the distribution of Astragalus strigulosus, A. tephrodes, A. thurberi, A. tijuanensis, and A. tioides in Mexico.