Herbs 3.5-5.5 cm tall, glabrous. Stems branched from base and middle, erect. Leaf blade lanceolate, 3-4(-7) × 0.5-1(-2) mm, apex extended into a pale bristle. Flowers in very condensed axillary cymes shorter than subtending leaf, 3- or 4(or 5)-merous on densely leafy axillary shoots usually shorter than subtending leaves; pedicel filiform, to 4 mm. Sepals linear-lanceolate, ca. 1.5 × 0.2 mm. Petals yellow, lanceolate, ca. 1 mm. Stamens to 1 mm. Nectar scales linear to spatulate, ca. 0.3 mm. Styles short. Follicle 2-seeded. Seeds brown, oblong, 0.4-0.5 mm. Fl. Sep.
The Chinese material of Tillaea alata is described as having yellow petals but is otherwise not distinguishable from the Indian and African material which has white to pale red petals. Material from tropical Africa has consistently 5-merous flowers and is included in subsp. pharnaceoides (C. A. Meyer) Wickens & Bywater.