Convolvulus aridus Greene subsp. intermedius Abrams, Contr. Dudley Herb. 3: 357. 1946; Calystegia macrostegia (Greene) Brummitt subsp. longiloba (Abrams) Brummitt; Convolvulus aridus Greene subsp. longilobus Abrams

Herbage glabrous or puberulent, usually glabrescent. Stems trailing or twining-climbing, to 300 cm. Leaf blades broadly to narrowly triangular, (7–)12–20(–30) mm wide excluding lobes, lobes 2-pointed or rounded, basal sinus usually acute to rounded, sometimes ± quadrate. Bracts lanceolate, (10–)13–20 × 6–10(–12) mm, prox­imally flat or ±keeled, apex acute. Flowers: sepals (9–)11–14(–16) mm; corolla (24–)27–40 mm; stamens (15–)17–21 mm.

Flowering Mar–Aug. Dry, stony hillsides; 0–600(–1100) m; Calif.; Mexico (Baja California).

Subspecies intermedia intergrades with subsp. macrostegia.