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A taxonomic revision of the genus Guatteria, including the former genera Guatteriella, Guatteriopsis and Heteropetalum is given. Within the genus Guatteria 177 species are recognized, 25 of which are new. Included are chapters on the history of the taxonomy of the genus, morphology, wood anatomy, karyology, palynology, chemistry, flower biology and pollination, dispersal, distribution and ecology, phylogeny and molecular studies, conservation, and uses. A synoptical key to all species is included, as well as two dichotomous keys, one for the species of Central America and Mexico, and one for the species of NE, E and SE Brazil. The species treatments include descriptions, full synonymy, geographical and ecological notes, vernacular names and taxonomic notes. For all species distribution maps are made. A complete identification list with all exsiccatae studied, an index to vernacular names and an index of scientific names is included at the end.

During the environmental impact study for a proposed nickel mine near Weda Bay on Halmahera in North Moluccas (Maluku Utara Province), Indonesia, two unknown Euphorbiaceae were discovered. Morphological comparisons and molecular phylogenetic analyses using four markers (plastid trnL‐F and rbcL, and nuclear ribosomal internal transcribed spacer and external transcribed spacer) indicated that they should be recognized as constituting a new, distinct genus of two species, which are described and illustrated here as Weda fragarioides and Weda lutea. The new taxa are members of the Australasian tribe Ricinocarpeae in subfamily Crotonoideae, and they are most closely related to Alphandia. In contrast with the otherwise mostly sclerophyllous Ricinocarpeae, Weda possesses stellate to dendritic hairs, large, long‐petiolate, glandular leaves, and inflorescences with a pair of large, leafy, subopposite bracts. The two narrowly distributed species are distinguished from each other by vegetative and floral features, molecular data, and elevational preferences. Leaf elemental analysis of Weda indicated manganese, but not nickel, accumulation. Newly resolved generic relationships and potential morphological synapomorphies within Crotonoideae are discussed, and the circumscription of Ricinocarpeae is expanded from 7 to 11 genera.

The genus Endospermum (Euphorbiaceae) in the Malay Archipelago (Malesia) comprises eight rather than the 10 species recognised in the latest revision by Schaeffer in 1971. Endospermum banghamii and E. ronaldii are synonymised with E. quadriloculare. The diagnostic characters for the genus are briefly discussed with special emphasis given to the myrmecophytic characters. The phylogenetic analysis, based on morphological characters (11 vegetative and 12 reproductive), resulted in a single, most parsimonious cladogram with bootstrap support only for the genus. The historical biogeographic analysis, used to evaluate the cladogram, showed that two species are placed in an unexpected position in the phylogeny, which means that the morphology-based cladogram may be reliable to a large extent.

Guatteria Ruiz & Pavón (1794: 85) is the largest genus of Annonaceae with about 210 recognized species (Chatrou et al. 2012, Maas et al. 2011). It comprises small- to medium- sized trees, rarely canopy trees or shrubs, and only two species are lianas, Guatteria scandens Ducke (1925:10) and G. fractiflexa Maas & Westra (2008: 491; Erkens et al. 2008). It is widely distributed throughout Mesoamerica, the Caribbean, and tropical South America (Erkens & Maas 2008). Species of Guatteria are common members of Neotropical forests where they occupy a wide variety of habitats, such as lowland rain forests, gallery forests, semideciduous forests, coastal forests, inundated forests, savannas and montane forests (Erkens et al. 2007b). However, the highest species diversity is found in the Amazon Basin with approximately half of the species occurring there. Central America harbours ca. 30 species, mostly endemics (Erkens et al. 2008) of which ca. 20 species occur in Panama, a highly under-collected country with respect to Guatteria (Erkens et al. 2006). In the adjacent Colombian Chocó region, we found ca. ten endemic species, and to date, only two species, Guatteria aberrans Erkens & Maas (2006: 201) and the new species described in this paper, are restricted to Panama and northwestern Colombia.