Astragalus oxyphysus A. Gray,

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

65. Astragalus oxyphysus A. Gray, Proc. Amer. Acad. 6: 218. 1864

Type:— USA, California, Arroyo del Puerto, in the Mt. Diablo range, on dry hills, 11 June 1860 –1862, Brewer 1259 (holotype: GH 00058858 digital image!: isotype: US 00004240 digital image!, CAS 0027665 digital image!, P 00585128 digital image!) .

Tragacantha oxyphysa Kuntze, Revis. Gen. Pl. 2: 947. 1891. — Phaca oxyphysa A. Heller , Muhlenbergia 2: 86. 1905.

Perennial. Stems up to 80 cm long, ascendant or erect, striate, basally hollow, villous, the trichomes of two different lenghts, the short ones, up to 1 mm long, sinuous, incurved or somewhat ascendant, mixed with longer and straight ones up to 1.6 mm long. Stipules 3–12 mm long, the lower ones clasping, connate for almost half of its lenght, ending in a bidentate ochrea, the upper ones semi-clasping, surrounding almost a half of the stem circumference, triangular to lanceolate. Leaves 4.5–18 cm long; leaflets 11–31, 4–33 mm long, lanceolate, elliptic, oblong, oblong-elliptic to obovate, acute to obtuse, truncate to mucronate, rarely retuse, white-tomentose when young, sometimes adaxially glabrescent. Peduncles 4–17.5 cm long; the racemes 4.5–25 cm long, flowers 20–65. Flowers white or cream, immaculate; the calyx 8.5–10.3 x 2.8–3.9 mm, villous, trichomes white, white, tan or black, the tube 5.9–8.4 mm long, campanulate to cylindrical, oblique, the teeth 1.6–3.7 mm long, subulate to triangular, the dorsal one shorter or sometimes longer than the rest; the banner 13.44–19 × 4–8 mm, recurved, oblanceolate, rhombic to obovate, subtruncate or slightly retuse; the wings 15–18 × 2–3 mm, the claw 7.4–8.9 mm long, the blade 8–9.8 mm long, slightly incurved, oblanceolate; the keel 13–15 × 2–3 mm, the claw 7.6–9.3 mm long, the blade 5.9–6.5 mm long, lunate, almost elliptic. Pod elevated from receptacle by a gynophore (articulated in the base of the pod) 3–11 mm long, spreading or pendulous, 2–4.5 × 0.6–1.6 cm, almost elliptic, oblique, elliptic to rhombic, inflated, bladder-like, basally narrowed, distally ending in a triangular beak, laterally compressed, bicarinate, the valves thin, pale green, turning papery, ochre, sub-diaphanous, shiny with age, finely reticulate, septum absent; ovules 11–18; seeds 3–4 mm long, mitten shape, brown, sometimes with purple tones, smooth.

Distribution:— Rare in Mexico recorded in northern Baja California, only at one locality, Ojos Negros (31°55’N – 116°18’W). Also, in Kern County, California ( USA) ( Fig. 20 ).

Habitat:— Low hills and plains; wayside; desert scrub; crop fields; 675 m.

Comments:— Along with A. oxyphysopsis , there are only two species of Astragalus that have inflated bladderlike in the central part but laterally strongly flattened pods, however, they can be discerned based on the continuity (stipe) or discontinuity (gynophore) of the structure that elevates the pod. In A. oxyphysopsis , the pod is continuous with the glabrous stipe (not articulated and thus the pod strongly attached to the receptacle), while in A. oxyphysus , the pod is sessile, but raised by a pubescent gynophore (articulated, from where it separates from the pod and therefore the pod weakly attached to the receptacle, soon caducous).

Specimens examined:— BAJA CALIFORNIA: 27 April 1980, 4 km NW of Ojos Negros and 1¼ km SSW of El Catorce, R. Moran 28353 ( ENCB, NY, TEX-LL) .

Figures

FIGURE 20. Map showing the distribution of Astragalus orcuttianus, A. oxyphysopsis, A. oxyphysus, and A. oxyrhynchus in Mexico.