Slender annual, 15-50 cm high, glabrous. Stem erect simple or with a few branches, striate. Leaf segments of lowermost leaves narrowly linear to filiform, sometimes slightly wider than the rest. Involucre dense. Sepals blue, broadly ovate, abruptly tapering into a distinct stipe. Petals with a distinct stipe, lobes of the outer (lower) lips obtuse. Follicles coherent for their full length, forming an inflated subglobose capsule. Seeds triquetrous, reticulate-rugose.