Pollen morphology of the family Polygalaceae (Fabales)

ABSTRACT

An overview of pollen morphology from all genera in the family Polygalaceae is presented to assist systematic studies of the Fabales clade. The pollen of 72 species, representing 18 genera, in Polygalaceae was examined using light microscopy and scanning electron microscopy. In addition, the pollen of eight species, representing seven genera, was examined using transmission electron microscopy. Pollen is described and illustrated for each genus, and the first pollen descriptions and publication of photomicrographs are presented for seven genera: Balgoya, Barnhartia, Comesperma, Diclidanthera, Eriandra, Moutabea, plus Polygala subgenus Badiera, and species previously included in Nylandtia (now in Muraltia). Pollen morphological similarities and differences broadly correspond with relationships suggested by recent molecular phylogenies. The aperture number was also found to correlate with trees generated using molecular data; early branching taxa have lower aperture numbers than later branching ones. The overall range of ectoaperture numbers seen in Polygalaceae, excluding Balgoya, is between five and 33. The pollen of Balgoya is tricolporate; all other genera have pollen with a range of ectoaperture numbers within each sample. The degree of endoaperture fusion to form endocingula is variable at a subgeneric level. All pollen is isopolar, except for that of Heterosamara and Polygala wattersii.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 156, 253–289.