Caudices to 10 dm × 1-6(-8) cm, clumps to 20 dm diam. Leaves without resinous odor; rosette 15-55-leaved, 5-25 cm diam.; blade whitish or light green, linear to triangular-lanceolate [-oblanceolate], laminar or semiterete, 5-25 × 0.6-3 cm, 2-8 mm thick, 2-5 times wider than thick, base 8-40 mm wide, surfaces sometimes farinose, not viscid, not oily. Inflorescences: cyme densely 2-5-branched and obpyramidal, or 15+-branched and cylindric, (branches scattered proximally); branches simple or 1-3 times bifurcate; cincinni 3-20-flowered, somewhat circinate, 1-10 cm; floral shoots (reddish), 1-7 dm × 2-15 mm; leaves 12-45, ascending, oblong, to 5 × 0.5-1.5 cm. Pedicels 1-3(-6) mm. Flowers: petals widespreading or slightly reflexed from middle, connate 1.5-2.5 mm, white or rosy, triangular-ovate or elliptic-oblong, 7-11 × 2-3.5 mm, apex acute, corolla 14-23 mm diam.; pistils connivent, suberect to ascending, 6-10 mm, (base tapering); styles 2-4 mm. Follicles ascending with adaxial margins 40-50º from vertical. 2n = 34, 68.

Subspecies extima Moran is endemic to Guadalupe Island, Baja California, Mexico.