Astragalus ervoides Hook. & Arn., Bot. Beechey Voy.

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

23. Astragalus ervoides Hook. & Arn., Bot. Beechey Voy. 417. 1840

Perennial. Stems up to 65 cm long, prostrate, decumbent o incurved-ascendent distally; minute strigose, the trichomes up to 0.4 mm long, appressed or totally glabrate in the inflorescences. Stipules 1–5 mm long, semi-clasping, not connate, lanceolate to triagular. Leaves 2–8 cm long; leaflets 11–25, 3–13 mm long, linear, ovate, oblong, elliptic to obovate, obtuse, retuse or retuse and mucronate apically, adaxially glabrous. Peduncles 3–9 cm long, curved or straight; the racemes 1.5–4 cm, flowers 5–40 soon deflexed. Flowers white, whitish, cream, pale yellow, yellowish, yellow-greenish (almost white), sometimes the keel purple to pinkish tipped; the calyx 3.4–7.3 × 2.2–9 mm, minute strigose, the trichomes black, the tube 2.1–3.8 mm long, campanulate, purple, papery; the teeth 0.7–4.2 mm long, lanceolate, triangular-deltate to acute triangular; the banner 6.2–10.2 × 3.4–6 mm, recurved, spathulate to sub-rhombic, retuse, with lilac veins; the wings 6.6–9.9 × 1.8–2.7 mm, the claw 2.6–4.2 mm long, the blade 4.4–7.3 mm long, oblong to oblanceolate, obtuse, truncate to retuse; the keel 5.5–7.7 × 1.4–3.2 mm, the claw 2.7–3.7 mm long, the blade 3.1–4.2 mm long, obovate. Pod 1.1–1.8 × 0.2–0.4 cm, commonly pendulous, sessile to short stitpitate (the stipe 0.4–2 mm long, persistent in the receptacule), triquetrous, ventrally carinate, dorsally deeply sulcate, laterally almost flattened or narrow angulate to obtuse, linear to narrow elliptic, slightly curved, basally abruptly narrow ending in a stipe, apically ending in a triangular, curved, 1–2.5 mm long beak, the valves thin, delicately reticulate, septum complete, the pod thence bilocular; ovules 10–22; seeds 1.8–2.2 mm long, yellowish to olive-green to green-brown, sublustrous.

Endemic to Mexico. In mountains of northwestern Mexico, southwest Chihuahua, southern Durango and Sinaloa, western and southwestern Nayarit, western Jalisco and north-central and western Michoacán.

It consists of two varieties recognized based on size of the leaves, peduncles, and the calyx teeth, and also number of ovules. A. ervoides y A. sinaloae are extremely similar in most of their features, both have stipitate pods, but, can be discerned by the ovary and fruit, both pubescent of A. sinaloae .

1. Stems 30–65 cm long; peduncles 4–9 cm long, longer than leaves; calyx teeth deltoid to wide triangular, 0.7–1.1 mm long; ovules 10–12; south Sinaloa, Nayarit, Jalisco, Michoacán, Tlaxcala ..................................................................... A. ervoides var. ervoides

- Stems 10–30 cm long; peduncles 3–7 cm long, shorter than leaves; calyx teeth subulate a to lanceolate, 1.2–4.2 mm long; ovules 12–21; Chihuahua and Durango, Sinaloa ................................................................................................. A. ervoides var. maysillesii