Pollen morphology of the Myrtaceae. Part 3: tribes Chamelaucieae, Leptospermeae and Lindsayomyrteae

The pollen morphology of 36 genera and 147 species from the Myrtaceae tribes Chamelaucieae, Leptospermeae and Lindsayomyrteae was surveyed using scanning electron microscopy (SEM) and light microscopy (LM). Syncolpate pollen were observed in all genera of Leptospermeae and some genera of Chamelaucieae. Genera of tribe Chamelaucieae displayed five distinct colpal morphologies, which makes it the tribe with the most diverse pollen in Myrtaceae. Six genera of Chamelaucieae, including Actinodium, Chamelaucium, Darwinia, Homoranthus, Pileanthus and Verticordia, produce large acolpate pollen not observed in any other Myrtaceae. Two of these genera produce distinct pollen; Actinodium is the only genus to have prolate-spheroidal shaped pollen, and Pileanthus pollen is large and dicolporate. A number of anomalous aperture types occurred in species of Chamelaucieae, including monocolporate (Homoranthus thomasii), pentacolporate (Calytrix oldfieldii) and hexacolporate (Sannantha tozerensis). Pollen of Lindsayomyrteae appeared similar to those of Leptospermeae and Chamelaucieae, and on the basis of pollen features, could be related to these two tribes.