Potamogetonaceae, Zosteraceae, and Cymodoceaceae

The three families of sea-grasses are treated together here, with a general introduction by Den Hartog and a key to the sea-grass genera. An extensive chapter on phytochemistry by R. Hegnauer (Leiden) has been included. Potamogetonaceae, pp. 174—196. The family comprises 3 genera and c. 80 species all over the world, of which in Malesia: Potamogeton (13 species) and Ruppia (1). The general part of the treatment covers c. 5 pages and includes a paragraph on pollen morphology by R.W.J.M. van der Ham (Leiden). Family, genera, and species are described and annotated. There are keys to the genera and species. Zosteraceae, pp. 197-200. The family consists of 3 genera and 17 species, of which only one genus (Zostera) with one species in Malesia. The general part of the treatment covers almost 2 pages and includes a paragraph on pollen morphology by R.W.J.M. van der Ham (Leiden). Family, genus, and species are described and annotated. Cymodoceaceae, pp. 201—216. The family comprises 4 genera and 14 species, mainly in tropical seas, of which in Malesia: Cymodocea (2 species), Halodule (2), and Syringodium (1). The general part of the treatment covers almost 2 pages and includes a paragraph on pollen morphology by R.W.J.M. van der Ham (Leiden). Family, genera, and species are described and annotated. There are keys to the genera and species.