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 <I>Guatteria</I> (<I>Annonaceae</I>) 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 <I>Guatteria</I> sect. <I>Mecocarpus</I> (Fries 1939) (the name derives from Ancient Greek &#956;&#951;&#954;&#969;&#957; = Poppy and &#954;&#945;&#961;&#960;&#959;&#962; = fruit: fruit resembling that of <I>Papaver</I> 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. <I>Mecocarpus</I> at present for convenience's sake. Additionally, the former genus <I>Guatteriopsis</I>, united with <I>Guatteria</I> a short time ago (Erkens &#38; Maas 2008b), is now also included in sect. <I>Mecocarpus</I>. The same applies to one of the two species attributed to <I>Guatteriella </I> (also merged with <I>Guatteria </I> by Erkens &#38; Maas 2008b), namely <I>Guatteriella tomentosa</I> R.E.Fr. (not <I>Guatteria tomentosa</I> Rusby) which is put into synonymy with <I>Guatteria trichocarpa</I> Erkens &#38; Maas. One new species is described, namely <I>Guatteria griseifolia</I> Maas &#38; Westra. The two species complexes of <I>G. guianensis</I> and <I>G. decurrens</I> are now treated each as a single polymorphic species. The present study falls within the framework of a planned monograph of the whole genus <I>Guatteria</I>.