CERASTIUM, MOUSE-EAR: A genus of the pentagynia order, belonging to the decandria class of plants; and in the natural method ranking under the 22d order, Caryophyllæa. The calyx is pentaphyllous; the petals are bifid; the capsule is unilocular, and opening at the top. There are 16 species, but none of them possessed of any remarkable property.