Sierra Madre Larkspur

Delphinium madrense hybridizes with D . carolinianum subspp. vimineum and virescens .

Stems 30-80(-100) cm; base often reddish, puberulent. Leaves cauline and basal; basal leaves 0-8 at anthesis; cauline leaves 3-11 at anthesis; petiole 1-15(-25) cm. Leaf blade semicircular to cordate, 2-8 × 2-10 cm, nearly glabrous; ultimate lobes 3-12, width 3-10 mm (basal), 2-6 mm (cauline). Inflorescences 5-75(-98)-flowered; pedicel 1-2.5(-5) cm, puberulent; bracteoles 2-4(-8) mm from flowers, green, lanceolate-linear, 3-5 mm, puberulent. Flowers: sepals dark blue to light blue, puberulent, lateral sepals spreading, 9-15 × 5-7 mm, spurs straight, ascending ca. 45(-90)° 10-15(-19) mm; lower petal blades elevated, exposing stamens, 4-7 mm, clefts 2-4 mm; hairs centered, densest on inner lobes near base of cleft, white. Fruits 15-21 mm, 3.5-4.5 times longer than wide, nearly glabrous. Seeds: seed coat cells with surfaces pustulate.

Tex.; Mexico (Coahuila, Nuevo León, and Tamaulipas).

Flowering spring-early summer.

Calcareous slopes, oak woods or desert scrub; 300-2100m.