Two new species of Malpighiaceae are proposed: Hiraea costaricensis C.E.Anderson and H. polyantha C.E.Anderson. Hiraea costaricensis is characterised by the presence of basifixed hairs on the stems and leaves; H. polyantha, of Colombia, is distinctive in its large inflorescences, composed of c.100 flowers. Collections of the novelties had been associated with Hiraea smilacina Standl., a species that traditionally had been thought conspecific with H. quapara (Aubl.) Sprague; they are immediately separated by their fruits. In Hiraea smilacina the schizocarps break into three butterfly-shaped samaras, as is typical for the genus. The fruit of Hiraea quapara is spherical, composed of three mericarps covered by a network of reduced winglets. Hiraea smilacina is found from southern Mexico through Central America, except El Salvador and Nicaragua, and has been collected also in Colombia and Ecuador. Hiraea quapara is known mainly from French Guiana, with one collection from adjacent Suriname and two from Amapá, Brazil. All taxa are fully described and illustrated.

An on-going controversy in community ecology involves the debate about the many factors that affect the assembly and composition of a given species assemblage. Theory suggests that community composition is influenced by environmental gradients or biotic processes. This study examines patterns of community composition in two tropical tree frog assemblages of primary and exploited lowland rain-forest sites in the Guiana Shield area of central Guyana, South America and the Upper Guinean rain-forest block of south-western Côte d'Ivoire, West Africa. We tested community composition and species abundance data of two adult tree frog communities collected on 21 standardized transects during a period of 5 y for evidence of spatial correlation in community composition. We applied simple and partial Mantel tests to separate the effects of environmental variables, spatial distance and spatial autocorrelation on community composition. Whenever environmental effects were accounted for, we found significant positive spatial correlation of community composition. All assemblages appeared to be spatially structured, i.e. sites in close proximity had similar species assemblages. However, spatially structured environmental variation (autocorrelation) did not account for the spatial structure of species incidence. Environmental factors did not prove to be significant predictors of species incidence in any of the assemblages analysed, even if we controlled for spatial effects. Observed correlation patterns of species composition were consistent within respective realms and disturbance regimes. Moreover, general correlation patterns were consistent between geographic regions. These results are in contrast to previously published results from a study on leaf-litter anurans and indicate that group-specific differences must not be neglected when analysing patterns of species composition in anurans as they may drastically alter the outcome of the analysis.