Abstract
New characters of the araphid marine diatom, Florella portoricensis Navarro, from subtropical waters are reported. These include stellate chloroplasts evenly distributed throughout the cell, presence of several structurally simple rimoportulae at both valve apices, cribrate areolae on valve and copulae, and fimbriae along entire advalvar edge of copulae. Based on these observations a new family, Florellaceae, is proposed, and the original descriptions of the genus and species are emended. For the present time, the new family has been placed in the order Striatellales along with the morphologically similar family Striatellaceae.