Cavicularia densa is the only species in the liverwort genus Cavicularia. The species was first described in 1897 by Franz Stephani, and is endemic to Japan, where it grows on fine moist soil. Plants are thalloid and flattened, with distinct upper and lower surfaces and a faint central strand. Thin scales grow from the underside in two rows, and in the region between the scales and the central strand are small ear-shaped domatia which harbor colonies of the blue-green alga Nostoc. The plants are dioicous, with the male antheridia and female archegonia produced by separate plants. Plants may also reproduce asexually from multicellular gemmae produced in crescent-shaped receptacles on the thallus surface.