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The floral biology of 3 species of Clusia sect. Chlamydoclusia and 3 species of Clusia sect. Cordylandra from Central Amazonia was investigated. The flowers of both sexes offer resin as the reward for pollinating bees. The male flowers of the species of sect. Chlamydoclusia may additionally offer pollen. Principal pollinators observed were bees, mainly of the tribes Euglossini and Trigonini. In the male flowers of sect. Chlamydoclusia the pollen is kept separately from the floral resin, but in sect. Cordylandra it is mixed with the resin. The elongated connectives of the fertile stamens in sect. Chlamydoclusia secrete droplets of an oily fluid which probably serves as accessory pollenkitt. The stigmas of the pistils and pistillodes of flowers of sect. Cordylandra secrete an oily fluid; possible functions of this are discussed. C. renggerioides has male plants with two different floral morphs; pollen of both produced fertile seeds when used to pollinate female plants. The taxonomic significance of the different pollination strategies in Clusia and their evolution is discussed.

The flower morphology and its relation to the pollination biology of four species of Clusia (Guttiferae) from the Gran Sabana (Guyana highland) belonging to three sections of the genus is described. The flowers of both genders of C. schomburgkiana (sect. Polythecandra) and of C. columnaris (sect. Omphalanthera) offer resin as a reward for small bees acting as pollinators. In both species the androecial morphology is highly derived. Functionally, this can be interpreted in terms of minimization of contact of the sticky resin and the pollen. Male flowers of C. pusilla and Clusia sp. of sect. Clusiastrum offer pollen as a reward for large, middle-sized and small bees, who vibrate the anthers to collect pollen. Female flowers are rewardless and unusual in the genus by the presence of long styles. The pollinating bees are probably deceived by the combination of papillose stigmas and the yellowish staminodes directly below these. The bees pollinate the stigmas when trying to vibrate them. The evolution of the flower biology in the genus Clusia is briefly discussed.

Cladistic relationships within the family Eriocaulaceae are investigated and discussed. A basal dichotomy dividing the family in two groups, Eriocaulon + Mesanthemum on the one hand, and the remaining genera on the other, is well supported by a number of synapomorphies. The division of the family into two subfamilies, Eriocauloideae and Paepalanthoideae Ruhland, is accepted. The relationships within the Paepalanthoideae need further study, especially in the large genus Paepalanthus, which is probably paraphyletic. The relationship of the genera Leiothrix and Syngonanthus (with Philodice informally included) as sister taxa, however, is well supported. A cladistic analysis of Leiothrix including 33 of its 37 species based on 47 characters was performed. The two shortest cladograms found and an alternative cladogram one step longer than the shortest ones are discussed. The evolution of some important characters and biogeographical implications of the results is investigated. With the exception of the widespread L. fjavescens no species are common to the "campos rupestres" of Minas Gerais and Bahia.