Molecular and Morphological Characterization of a New Monotypic Genus of Annonaceae, Mwasumbia from Tanzania

Abstract

The coastal lowland rain forests of eastern Africa are well known for their high levels of plant endemism. A new genus of Annonaceae, Mwasumbia, is described from Tanzania, underscoring this high biodiversity and represented by a single species, Mwasumbia alba. The new genus presents several morphological characters suggesting a close relationship to two other African genera, Greenwayodendron and Polyceratocarpus. Maximum parsimony and Bayesian molecular phylogenetic analyses based on two plastid markers, rbcL and the trnL-trnF region, strongly support the close relationship of these three genera to one another as well as to two other African genera, Annickia and Piptostigma. Together these five genera form a moderately supported clade within the so-called short-branch clade of Annonaceae. A detailed morphological and palynological comparison between Mwasumbia and the four other genera shows that this new genus exhibits a combination of features unique within this group: intermediate tertiary leaf venation, exclusively bisexual flowers, slightly imbricate sepals, valvate petals, outer and inner petals equal in length, numerous stamens, four carpels, few and uniseriate ovules, few and sessile monocarps, and verrucate sulculate pollen grains. Phylogenetic analyses also suggest the genus Piptostigma, as currently circumscribed, to be paraphyletic. An IUCN conservation status of VU D2 is proposed, reflecting the narrow distribution of the single species.

Ethnopharmacological survey of Annonaceae medicinal plants used to treat malaria in four areas of Cameroon

“…In this study Annickia chlorantha and Annickia affinis are distinguished as two different species, Annickia chlorantha being the rarer species (Couvreur et al, 2009). Thus, plants described in the four study sites as Annickia chlorantha most likely represent the two species.…”

<p class="HeadingRunIn"><strong>Characterization of <em>Hubera</em> (Annonaceae), a new genus segregated from <em>Polyalthia</em> and allied to <em>Miliusa</em></strong></p>

“…Pollen data (SEM and/or TEM) for Monoon and Polyalthia s.s. were available for comparisons (Table 1). The pollen material for SEM was not acetolysed, following Chaowasku et al (2008) and Couvreur et al (2009). The material for TEM was prepared following Van der Ham (1990).…”

“…Even before the advent of molecular analyses, species had been removed from the genus on morphological grounds. For example, the new genus Greenwayodendron Verdcourt (1969: 89) was established to accommodate two African species now known to be closer to a suite of African genera (Couvreur et al 2009), Johnson (1989) removed two species to the genus Disepalum Hooker (1860: 156), following the pollen morphology studied by Walker (1971) and Maasia Mols, Keßler & Rogstad in Mols et al (2008: 493) was recognized following Rogstad's (1989) systematic studies, although monophyly of the last genus had been demonstrated in phylogenetic analyses by Mols et al (2004a). Phylogenetic analyses have led to removal of additional species to Marsypopetalum Scheffer (1870: 342;Xue et al 2011), Fenerivia Diels (1925Saunders et al 2011), and Monoon Miquel (1865: 15;Xue et al 2012).…”

A new species in the tree genus Polyceratocarpus (Annonaceae) from the Udzungwa Mountains of Tanzania

“…& Diels (Annonaceae subfamily Malmeoideae, tribe Piptostigmateae, Chatrou et al 2012) is distinguishable from other African genera of the family by the combination of a tree habit, percurrent tertiary veins of the leaves, axillary (sometimes cauliflorous) inflorescences, occurrence of both staminate and bisexual flowers, petals of the outer and inner whorls roughly equal in size and shape, numerous monocarps with multiple seeds arranged in a single row, and pitted seeds with spiniform ruminations (Couvreur et al 2009, Couvreur et al 2012). Engler and Diels (1900) published the genus based on Polyceratocarpus scheffleri Engler & Diels, collected in the Usambara Mountains.…”