The features of the thallus and particularly spore morphology is useful for identifying Riccia species. Species of Riccia are broadly divided into two groups based on the appearance of the thallus surface. In one group, the thalli appear smooth and in the other the thalli appear perforated or cavernous.

R. crinita is one of the most distinctive of the genus, the thallus being fringed by white hairs. R. sorocarpa is one of the most common.

Two species, R. tasmanica and R. weymouthiana are poorly known.