An overview of pollen morphology and its systematic significance in tribe Vaccinieae (Vaccinioideae: Ericaceae)

摘要

In addition to our previous palynological study on Vaccinium, the pollen morphology of 59 species from the other 22 genera in the tribe Vaccinieae has been studied using light and scanning electron microscopy. The total morphological diversity of thepermanent pollen tetrads of the tribe has been summarized here. Apart from the seven main types (Types 1 - 7) and twelve subtypes of Vaccinium, one new type (Type 8 from Agapetes bracteata) and two new subtypes, within the Type 5, are also recognized, based on apocolpial exine sculpture. The present results for Dimorphantera show that exine sculpture is the most important pollen morphological feature to identify the probable monophyly of one genus in the Vaccinieae. The exine sculpture of Agapetes species supports a close relationship between Agapetes and Vaccinium, and may even support the inclusion of Agapetes in Vaccinium, with the possible exception of A. bracteata. The exine sculpture of Costera endertii (Type 7) is very similar to that of V. stamineum of monotypic sect. Polycodium (Vaccinium). Within the Andean clade palynological features do not support a division into two major subclades, and may support the monophyly of Macleania. As in previous studies, our palynological observations supporta sister relationship between Cavendishia and Satyria, and indicate two distinct groups at least among the Thibaudia species. The close relationship between Gaylussacia and Vaccinium is also supported by pollen morphology.