A taxonomic survey of Guatteria section Mecocarpus including the genera Guatteriopsis and Guatteriella p.p. (Annonaceae)

This paper deals with a group of species of the Neotropical genus Guatteria (Annonaceae) which are characterized by leaves with tiny warts (verruculae) on both surfaces and by elongate and short-stipitate monocarps (i.e., the length of the monocarp body surpassing the length of the stipe). These species were placed by Fries in Guatteria sect. Mecocarpus (Fries 1939) (the name derives from Ancient Greek μηκων = Poppy and καρπος = fruit: fruit resembling that of Papaver species). All occur in South America, none having been found elsewhere so far. Although there is much doubt nowadays about the taxonomic significance of Fries's sections, we maintain sect. Mecocarpus at present for convenience's sake. Additionally, the former genus Guatteriopsis, united with Guatteria a short time ago (Erkens & Maas 2008b), is now also included in sect. Mecocarpus. The same applies to one of the two species attributed to Guatteriella (also merged with Guatteria by Erkens & Maas 2008b), namely Guatteriella tomentosa R.E.Fr. (not Guatteria tomentosa Rusby) which is put into synonymy with Guatteria trichocarpa Erkens & Maas. One new species is described, namely Guatteria griseifolia Maas & Westra. The two species complexes of G. guianensis and G. decurrens are now treated each as a single polymorphic species. The present study falls within the framework of a planned monograph of the whole genus Guatteria.