General:
Annual herb from a taproot, short curly- or stiff-hairy (or appressed-hairy) throughout; stems simple or branched above, 5-50 cm tall.

Leaves:
Basal leaves oblanceolate, often deciduous, 2-6 cm long, to 1 cm wide; stem leaves linear or linear-oblong to oblanceolate, reduced upward to the leafy, lanceolate bracts of the inflorescence, unstalked or nearly so, entire, alternate.

Flowers:
Inflorescence of narrow, elongating clusters that have bracts throughout; flower stalks ascending to erect when in fruit; petals blue or white, fused at base into small (2-4 mm long) tube that flares a bit (1.5-2.5 mm wide) at the top to 5 lobes, with 5 yellow bulges at the throat; fruiting calyces 3-3.5 mm long, the lobes erect.

Fruits:
Nutlets 4, clustered together, egg-shaped, 2-3 mm long, with a crown of marginal, barb-tipped prickles in a single row, prickles distinct or sometimes fused at the base to form a cuplike rim.

Note: Two varieties occur in BC:
1. Prickles of nutlets distinct to base; the common variety var. occidentalis
1. Prickles of nutlets fused at base, forming a cup; rare var. cupulata (A. Gray) Higgins

Source:  The Illustrated Flora of British Columbia