Plants 100-550 mm long. Corm with a crescent-shaped basal ridge. Stem short, hidden, or up to 300 mm long. Basal leaf single in long-stemmed forms, filiform or compressed cylindrical, 100-550 x 0.8-3(-4) mm, suberect or curved, sometimes minutely ciliate on the rib margins, grooves wide or narrow. Inner bract membranous or with the centre sometimes submembranous. Flowers (18-)20-40 mm long, yellow or white, sometimes blue, blue-violet or rarely pink, cup yellow or greenish yellow, outer segments green or greenish brown on the backs. Perianth tube 3-7 mm long; segments 10-30 x 3-12 mm. Filaments 4-7 mm; anthers 4-7 mm, golden yellow. Style 8-15 mm; stigmas more or less at the anther tips. Capsules shortly cylindrical, on recurved peduncles which straighten later.
Cormous geophyte, mostly 50-150 mm tall, stem underground or reaching 150 mm above ground; corm with a crescent-shaped basal ridge. Leaves 3 or 4, often wider and clasping below. Flowers white or yellow (occasionally blue or pink with yellow cup), outer tepals uniformly green outside, sometimes scented; outer bract green with narrow hyaline margins, inner bract ± membranous, often brown-streaked.
Cormous geophyte, 5-30 cm, corm with an oblique basal ridge, basal ridge fibrous, stem short or branching just above ground. Basal leaves 1 or 2, clasping below. Flowers white or yellow, rarely blue or pinkish, with yellow cup, inner bracts papery.
See Romulea flava var. minor.