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:
Rip Rap. QUIKRETEÂ® Rip Rap - Scrim (No. 1134-80) is a commercial grade blend of Portland cement and specially graded sand, packaged in a fiber reinforced, biodegradable bag for erosion control applications. Rip Rap requires no mixing or equipment to install.