General:
Perennial herb from a simple or branched stem-base; stems erect, several, branched above, long woolly-hairy and more or less glandular-hairy, 20-60 cm tall.

Leaves:
Basal leaves few, soon deciduous; stem leaves opposite, 4-7 pairs, oblanceolate below to lanceolate above, long woolly-hairy and more or less glandular-hairy, 6-7 cm long, 0.5-1.5 cm wide, unstalked and slightly fused; stipules lacking.

Flowers:
Inflorescence of several to many flowers in a leafy and usually compact cluster; petals 5, white, stalklike at the bases, the stalks about 15 mm long, the blades very short, egg-shaped, about 2 mm long, entire or shallowly notched at the tip, the appendages 4 (5-6); sepals 5, united, forming a tube about 15 mm long at flowering time, becoming more nearly club- or bell-shaped in fruit, 10-nerved.

Fruits:
Capsules oblong, 1-celled; seeds light brown, 2.0 mm long, corrugate-wrinkled and inflated.

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.