Comparative Pollen Morphology of the American Myristicaceous Genera Otoba, Iryanthera, and Osteophloeum

Pollen of the American myristicaceous genera Otoba, Iryanthera, and Osteophloeum was studied with light, scanning electron, and transmission electron microscopy. Formal generic pollen descriptions are provided for each genus, all three of which possess distinctive pollen that is most readily distinguished by characters of exine structure and sculpturing. Pollen of Otoba has a basically granular interstitium with pendent granules attached to the inner face of the basically imperforate tectum and an unique patch of well‐developed columellae and a semitectate reticulum on its presumed proximal face. The somewhat similar, distinctly columellate, tectate‐perforate to semitectate pollen of Iryanthera and Osteophloeum may be distinguished by a reticulum that is beadlike in the former and psilate in the latter. Pollen of Iryanthera is more or less indistinguishable from that of the previously studied African myristicaceous genus Coelocaryon.