Plants 13-70 cm. Stems uniform toward base, 0.7-3.4 mm diam.; bracts 2-6(-12). Leaves ± prostrate; blade 6.5-15 × 1.5-3 cm. Inflorescences densely flowered, 4-40 cm; rachis usually longer than peduncle; bracts 5-11 mm. Flowers pale green, translucent; fragrance nocturnal, delicate, ± lemony or otherwise pleasant; sepals oblong, 2.5-5 × 0.7-1.6 mm; lateral sepals recurved; petals erect, strongly upwardly recurved, straight, linear, spreading to form a V, 3-6 × 0.6-1.3 mm, apex long-acuminate; lip projecting to ± deflexed, narrowly lanceolate, 2.5-5 × 0.8-2.5 mm; spur deflexed, curved, tapered, 4-9 mm; viscidia broadly elliptic-ovate, 0.25-0.45 × 0.2-0.3 mm; rostellum slightly elongate. Capsules 4-9 mm. Seeds cinnamon brown.

Flowering May--Jul. Woodlands and chaparral, sometimes on serpentine soils; 100--2200 m; Calif.

Piperia leptopetala is uncommon but widely distributed in California. Its flowers have the narrowest sepals and petals of the genus; this gives the inflorescence a lacy appearance. Piperia leptopetala blooms earlier than sympatric P. transversa and P. elongata, two species with which it is sometimes confused.