Astragalus comonduensis A. E. Estrada, Rebman & Villarreal,

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

15. Astragalus comonduensis A. E. Estrada, Rebman & Villarreal, Phytotaxa 391(1): 59–60. 2019

Annual plant, caulescent. Stems erect, up to 45 cm long, striate, green or green-reddish, turning purple when dry, strigulose, the trichomes 0.2–0.5 mm long, white, straight, appressed. Stipules free or some clasping by half to threequarters of stem´s circumference, straight or basally oblique, 2–3 × 1–2 mm, ovate to triangular-lanceolate, brownyellow, strigulose abaxially, the trichomes 0.2–0.5 mm long, white with some black ones intermixed, glabrate adaxially, margins ciliate. Leaves 2–7.9 cm long; leaflets 13–21, 3.2–17 × 1.4–4 mm, elliptic to elliptic-obovate, base acute, apex mucronate, mucro 0.1–0.3 mm long, glabrate adaxially, strigulose abaxially with white trichomes. Peduncles 3.8–4.9 cm long, erect, ascending, sparsely strigulose, with both white and black trichomes; racemes 1.6–4.4 cm long, 4–9 flowered; flowers mostly ascending, and remaining so in fruit, rarely spreading. Flowers purple-lavender, some flowers becoming bluish with age, the calyx 2–2.8 × 1–1.2 mm, campanulate, the tube 2–2.8 mm long, slightly inequilaterous, strigulose, with white and black trichomes, the teeth 0.8–1.2 mm long, lanceolate to triangular-lanceolate, green, greenreddish to reddish, sparsely strigulose as the tube; the banner sessile, 4.5–5 × 2.1–2.2 mm, elliptic to elliptic-obovate, sometimes longitudinally inequilaterous, recurved, apically retuse; the wings 4.2–4.6 × 1.3–1.4 mm, the claw 2–2.1 mm long, the blade 2–2.3 mm long, oblong, oblique, half-obovate, the apex rounded; the keel 3.9–4 × 1.2–1.3 mm, the claw 1.8–1.9 mm long, the blade 1.9–2 mm long, incurved, half obovate, apically triangular, the beak curved slightly backwards. Pod ascending when young and remaining so, sessile, oblique-ovoid, subglobose, bladdery-inflated, 10– 14 × 6–10 mm, basally somewhat cuneate, distally abruptly contracted in a triangular, slightly laterally compressed, 2–3 mm long beak, ventrally shallow sulcate by the filiform suture and it less convex than the also filiform dorsal suture, the valves little flattened dorsoventrally, sparsely and minute strigulose, the trichomes 0.1–0.3 mm long, tan to reddish, becoming purple when dry, subdiaphanous to opaque; ovules 7–9; seeds 2.1–2.5 mm long, opaque, smooth, light-brown to brown.

Distribution:— Species endemic to Mexico, exclusively of Baja California Sur, restricted to Llano La Laguna in the Sierra La Giganta region, north of San José de Comondú ( Fig. 4 ).

Habitat:— This species grows in wet muddy soil near the water’s edge along the banks of ephemeral lakes.

Comments:— This species resembles A. aridus , but A. comonduensis reaches up to 42 cm tall, and its stems are erect. The pubescence of A. comonduensis is strigulose, 0.2–0.5 mm long, straight, with white and appressed trichomes, while, in A. aridus is silky or satiny-canescent, with ascending 0.6–1.1 mm long trichomes. The calyx of A. comonduensis is shorter (2–2.8 mm long) and narrower, than that of A. aridus (3.2–4.4 mm long), plus it exhibits both with white and black intermixed trichomes unlike the uniformly white trichomes of A. aridus . Astragalus comonduensis has purple-lavender petals while A. aridus has whitish, pink-lilac or flesh color flowers. The pods of A. comonduensis is completely inflated, bladdery, proportionally wider, shiny, and not laterally compressed (not even a little), opaque to sub-diaphanous, and minutely-strigulose, while the pods of A. aridus are little inflated, but not bladdery, laterally compressed at both ends, and strongly so at the apex, with the valves densely white canescent to strigulose-pilose, papery, and opaque. Astragalus insularis and A. idrietorum , also found on the Peninsula of Baja California and are physiognomically somewhat similar to A. comonduensis , but these two last species can easily be distinguished by their much longer perianth parts.

Specimens examined:— BAJA CALIFORNIA SUR: 9 March 2016, Llano La Laguna : Sierra de la Giganta Region, north of San José de Comondú near Rancho Palo Fierro; J. Rebman 31220, R. Domínguez Cadena, F. Pio León ( SD); 14-III- 20002, La Laguna, al norte de San José de Comondú, M. Dominguez L. 3140 ( SD).

Figures

FIGURE 4. Map showing the distribution of Astragalus coahuilae, A. cobrensis var. maguirei, A. coccineus, A. comonduensis, and A. coriaceus in Mexico.