or horn-flower: A genus of the order of algeæ, belonging to the cryptogamia clas of plants; and, in the natural method, ranking under the 57th order, Algeæ. The essential characters are: The calyx of the male is sefifie, cylindric, and entire; the antheræ (one) is subulate, very long, and two-valved: The calyx of the female is monophyllous, divided into five parts, and expanding: The seeds are about three, naked and roundish.—There are only three species of the anthoceros, viz. the punctatus or spotted anthoceros, a native of Britain; the levis, a native of Europe.