Pollen morphology and systematics of palaeotropical Phyllanthus and related genera of subtribe Phyllanthinae (Euphorbiaceae)

• Published in: Botanical journal of the Linnean Society Vol. 157; no. 4; pp. 591 - 608
• Main Authors: WEBSTER, GRADY L, CARPENTER, KEVIN J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.08.2008; Blackwell Publishing Ltd
• Subjects: Breynia; Emblica; Eriococcus; Euphorbiaceae; Flueggeinae; Glochidion; Isocladus; Phyllanthus; Sauropus; scanning electron microscopy
• ISSN: 0024-4074; 1095-8339
• DOI: 10.1111/j.1095-8339.2008.00781.x

The observations of pollen from 27 species of subtribe Phyllanthinae using scanning electron microscopy reveal considerable morphological diversity in palaeotropical Phyllanthus and the related palaeotropical genera Breynia, Glochidion, and Sauropus. The tribe appears to be monophyletic, but the pollen morphology does not support the monophyly of Phyllanthus or Sauropus. Within Phyllanthus, the pollen characters suggest a close relationship between the subgenera Emblica and Phyllanthodendron. They also reveal a surprising morphological congruence between the pollen grains of section Ceramanthus (subgenus Isocladus) and those of subgenus Eriococcus, although it is not clear whether this similarity is homoplastic. The presence of diploporate colpi is a synapomorphy uniting Breynia and Sauropus, but may be homoplastic in Phyllanthus. The affinities suggested by the morphological features of the pollen in the Phyllanthinae are concordant with recent molecular phylogenies.