Sobre el genero zannichellia l. (zannichelliaceae)

Suimmary. The caryology, anatomy, floral biology and ecology are used in an intent to revise the genus Zannichellia. Six species are recognized, grouped into two sections: sect. Zannichellia, with Z. palustris L., Z. pedunculata Reichenb. and Z. major Boenn. ex Reichenb., polyploids with male and female flowers usually in a same node and short staments with bilocular anthers, and sect. Monopus Graebner, with Z. obtusifolia Talavera, Garcia & Smit, Z. contorta (Desf.) Chamisso & Schlecht. and Z. peltata Bertol., diploids with male and female flowers in differen nodes and long staments with tetralocular anthers. A key to the species is given, together with the correct name, synonimy, description, distribution and studied material for each recognized species. A new species, Z. obtusifolia, is described.