PLANT: Annuals or perennials; stems simple to much branched, erect to decumbent, leafy. LEAVES: opposite, rarely alternate above, palmately lobed, the lobes confluent with the rachis, linear, flat to terete, acute to weakly spinulose. INFLORESCENCE: terminal and compact or axillary, glabrous to pubescent or glandular. FLOWERS: pedicelled, actinomorphic; calyx tube membranes usually ruptured or distended in fruit, the lobes equal, linear to attenuate, often mucronate; corolla white to yellow or lavender; stamens equally inserted on the corolla throat or tube; anthers slightly exserted or included; filaments equal in length; style included to exserted. CAPSULE: ovoid to oblong; seeds 1-several per locule. NOTES: Ca. 30 spp. in sw N. Amer. and S. Amer. (Greek: lepto = narrow + siphon = tube). REFERENCES: Dieter H. Wilken and J. Mark Porter, 2005, Vascular Plants of Arizona: Polemoniaceae. CANOTIA 1: 1-37.