Plants (glaucous), glabrous throughout. Stems unbranched or branched (few) distally, 1.5-3 dm. Basal leaves (not seen), withered by flowering. Cauline leaves: petiole 0.4-1.6 cm; blade margins pectinate or pinnatisect, lobes filiform to linear, 0.5-1.5 cm × 0.2-0.8 mm, margins entire. Racemes (lax); rachis flexuous. Fruiting pedicels divaricate-ascending, straight, (2-)3-10(-15) mm. Flowers: sepals 2.2-3 × 0.7-1 mm; petals purple or lavender, 3.5-6 × 2-3 mm, claw ca. 1.5 mm; median filaments 2-2.7 mm; anthers oblong, 0.6-0.8 mm. Fruits divaricate-ascending, straight, subtorulose, 2.5-4.1 cm × 0.7-0.9 mm; ovules 32-40 per ovary; style 0.5-0.8 mm. Seeds 1-1.3 × 0.6-0.9 mm.

Flowering Apr. Dry ridges; of conservation concern; ca. 0 m; Calif.

Sibara filifolia is known from Santa Cruz Island. It is in the Center for Plant Conservation´s National Collection of Endangered Plants.