The fronds of tree ferns are usually very large and multiple-pinnated, but at least one type has entire (undivided) fronds. The fronds of tree ferns also exhibit circinate vernation, meaning the young fronds emerge in coils that uncurl as they grow.he order Cyatheales, which includes the tree ferns, is a taxonomic division of the fern class, Polypodiopsida.
rap noun (MUSIC) A2 [ U ] a type of popular music with a strong rhythm in which the words are spoken, not sung:
For more information on the music genre, see Hip hop music. Rapping (or emceeing, MCing, or rhyming) is a musical form of vocal delivery that incorporates rhyme, rhythmic speech, and street vernacular, (slang) which is performed or chanted in a variety of ways, usually over a backbeat or musical accompaniment of beats.