Generic limits in the seagrass family Zosteraceae

The seagrass family Zosteraceae may be divided into four groups of species on the basis of morphological and developmental evidence. It is proposed to treat each of these groups as a genus; this involves the elevation of Zost erella from subgeneric to generic rank as Nanozostera. The family thus now includes: Heterozostera (one sp.), Nanozostera (eight spp.), Phyllospadix ( five spp.), and Zostera (four spp.). Molecular and morphological evidence s uggests that Phyllospadix is the most divergent taxon, while Heterozostera and Nanozostera are the most closely related.