Pollen morphology of the Phyllanthus species (Euphorbiaceae) occurring in New Guinea

Abstract

Thirty-eight species from New Guinea have been examined and their pollen grains could be grouped into nine pollen types. Five of these types are more or less morphologically related. The largest type, the P. aeneus type, comprises 17 species and represents the section Nymania (K. Schumann) J.J. Smith, P. flaviflorus excepted. Its pollen grains show most advanced features. The related P. acinacifolius type, including five species of the section Gomphidium (Baillon) Webster and one species (P. flaviflorus) of the section Nymania, shows less advanced features in its pollen grains. The P. casticum type has three species belonging to the subgenus Kirganelia (Jussieu) Webster section Anisonema (A. Jussieu) Grisebach). The P. archboldianus type with the single species P. archboldianus is undoubtedly related to the P. casticum type but clearly different in ornamentation. The P. maritimus type with two species, one in the section Adenoglochidion (Mueller Arg.) Mueller Arg and another provisionally placed in the section Anisonema are very much alike and probably represent a new taxonomic section. The pollen grains are intermediate between those of the P. casticum type and the P. aeneus type.

The P. buxifoliu type as well as the P. virgatus type are both newly described types, but as most representatives occur outside New Guinea, a detailed comment is postponed.

The P. amarus type and the P. urinaria type have been described in previous papers and are not repeated herein.