Djinga cheekii sp. nov. (Podostemaceae) from Cameroon

A new species is added to the monotypic African genus Djinga. Djinga cheekii Ghogue, Huber & Rutish. (Podostemaceae) is described as a new species from Cameroon (Littoral Province) and its morphological affinities and conservation status are assessed. The main distinguishing characters are: stamens 2 (not 1 as in D. felicis), flower buds inside spathella strongly inclined (not only slightly inclined as in D. felicis), and stems lacking or only up to 6 mm long (not up to > 6 cm as in D. felicis). A molecular analysis revealed that D. cheekii is sister to D. felicis, and both together are sister to Ledermanniella linearifolia and L. pusilla which show completely inverted flower buds inside the spathella, as typical for the large and still artificial genus Ledermanniella

Taxonomic revision of the African genera Brieya and Piptostigma (Annonaceae)

International audienceBackground and aims – Annonaceae are an important family in tropical rain forests of Africa. Here, we present a revision of the west-central African genus Piptostigma of the tribe Piptostigmateae. Previous molecular phylogenetic analyses of Piptostigmateae have revealed that the genus as currently circumscribed is paraphyletic. The aims of the article are: (1) to clarify the generic delimitation of the genus Piptostigma, especially in relation to its current polyphyletic delimitation; (2) to provide a new updated key to the genera of tribe Piptostigmateae; and (3) to provide for the first time in over 100 years a complete taxonomic revision of genera Brieya and Piptostigma.Material and methods – Normal practices of herbarium taxonomy were used for the morphological study of about 200 specimens from B, BR, BRLU, G, HBG, K, L, LBV, LISC, MO, P, U, US, WAG, YA and Z. We sequenced three plastid regions for 32 samples representing 26 ingroup (Piptostigmateae) and six outgroup species in order to explore the paraphyly of Piptostisma. The open source software QGis was used to generate the distribution maps of the species and their conservation status was obtained using the IUCN categories and criteria.Key results – Molecular and morphological evidence support the reinstatement of the genus Brieya De Wild. Three keys are presented, one to the genera of Piptostigmateae and the two others to the species of Brieya and Piptostigma. A total of thirteen species are described for Piptostigma and two for the genus Brieya. Four new species are presented for the genus Piptostigma: P. macrophyllum, P. mayndongtsaeanum, P. goslineanum and P. submontanum

Memecylon Batekeanum, a New Species from Southeastern Gabon, and a Note on the Circumscription of Memecylon Sect. Mouririoidea (Melastomataceae)

Volume: 16Start Page: 276End Page: 28

Taxonomic revision of Saxicolella (Podostemaceae), African waterfall plants highly threatened by hydro-electric projects

Species of the genus Saxicolella Engl. (Podosteniaceac) arc African rheophytes, restricted to rapids and waterfalls as are all members of the family. Previously, Saxicolella sensu lato was shown to be polyphyletic with two separate clades. The name Pohliella Engl. was recently resurrected for one Glade that is sister to the American genera Ceratolacis (Tul.) Wedd., Podostemum Michx. and all Old World Podostemoideae. Pohliella has distichous phyllotaxy, bilocular ovaries, filiform roots with paired holdfasts, and rootcaps. The second Glade, Saxicolella sensu stricto, including the type of the generic name, has spiral phyllotaxy, unilocular ovaries, ribbon-like or crustose roots that lack both holdfasts and rootcaps. Saxicolella sensu stricto, sampled from the type species, S. nana Engl. of Cameroon, is embedded within and near the base of the major Glade of African podostemoids and is sister to all other African genera apart from Inversodicraea R.E.Fr. and Monandriella Engl. Recently reduced to three species in Cameroon and SE Nigeria by the resurrection of Pohliella, Saxicolella sensu stricto is expanded to eight species in this monograph by description of five new taxa. Saxicolella futa Cheek and S. deniseae Cheek are newly described from Guinea, S. dim Cheek from Cameroon, the informally named S. sp. A from Gabon, and S. angola Cheek from Angola. The known geographic range of the genus is thus expanded c. 2,500 km westwards to Guinea from eastern Nigeria and c.1,500 km southeastwards from near Yaounde to Cuanza do Sul, Angola. The greatest concentration of species occurs in the Cross-Sanaga interval of western Cameroon and eastern Nigeria, with three species. Cameroon (3 species) followed by Nigeria and Guinea (2 species each) are the countries with highest species diversity. A classification is proposed grouping the species into three subgenera (Saxicolella, Butumia (G.Taylor) Cheek comb. et stat. nov. and Kinkonia Cheek subgen. nov.) based on root morphology and shoot position and morphology. The discovery, morphology, circumscription, distribution and ecology of Saxicolella is reviewed, an identification key to the species is presented, together with descriptions, synonymy and links to illustrations. All of the species are provisionally assessed as either Endangered or Critically Endangered using the IUCN 2012 Red List Criteria. The major threats, above all, are hydro-electric projects. Saxicolella deniseae may already be globally extinct, and two of the four known locations of S. angola appear lost, S. sp. A of Gabon is threatened at at least one of its three locations, while S. futa is threatened at all three locations. Contamination of watercourses by increased turbidity from silt-load due to anthropic changes and by eutrophication from pollution are also threats for the majority of the species

Flora of Cameroon – Annonaceae Vol 45

Annonaceae is a major pantropical family with 113 genera and about 2550 species. Cameroon is one of the most biodiverse countries in Africa but its flora remains incompletely known. In this volume of the Flora of Cameroon, we describe 166 native taxa representing 163 species in 28 native genera within the family Annonaceae. A total of 22 species (about 13%) are endemic to the country. We provide keys to all native genera, species, and infraspecific taxa. For each species a detailed morphological description and a map of its distribution in Cameroon are provided. Distribution maps and diversity analyses are based on a taxonomically verified database of 2073 collections. Across Africa, Cameroon is a center of diversity for Annonaceae harboring one of the highest numbers of species and genera. For example, Cameroon harbors the highest number of African species for the only pantropical genus of Annonaceae, Xylopia. Annonaceae are found across all 10 administrative regions of Cameroon but diversity is concentrated within the tropical rain forest areas situated in the south and South-West. The areas around Bipindi and Mount Cameroon show the highest levels of diversity, but this is correlated with collection effort. Line drawings and/or photographs accompany most species. One species new to science Uvariopsis etugeana Dagallier & Couvreur sp. nov. is described. We also undertake a number of nomenclatural changes such as lectotypifications, six new synonymies and two new combinations (Uvaria anisotricha (Le Thomas) Couvreur, comb. nov.; Uvariodendron fuscum var. giganteum (Engl.) Dagallier & Couvreur, comb. nov.)

How to get off the mismatch at the generic rank in African Podostemaceae?

The Podostemaceae are highly enigmatic plants which are restricted to submerged river-rock habitats. The availability of new material of nine taxa from continental Africa prompted this new study. Five species belonging to the genera Dicraeanthus, Leiothylax, Letestuella, Macropodiella, and Stonesia and another four species of the large genera Inversodicraea sensu stricto and Ledermanniella sensu stricto have been analysed for the first time. New anatomical and developmental data are described and illustrated by use of microtome sections and scanning electron microscopy. In parallel, phylogenetic analyses of all available sequence data of African Podostemaceae have been conducted using three plastid markers (matK, trnD-trnT, rpoB-trnC). Inversodicraea cf. bosii appears basal within the continental African clade. The remaining taxa are distributed in three, rather poorly supported, major clades which are consistent with their morphology: (1) the Inversodicraea clade is characterised by stem scales and contains members of the former Ledermanniella subg. Phyllosoma with either pollen-monads or dyads; (2) the Ledermanniella-Monad group consisting of Leiothylax, Letestuella, Macropodiella, Stonesia, and Ledermanniella species—all taxa without stem scales but showing pollen as single grains, with Monandriella linearifolia being basal to this clade; (3) the Ledermanniella-Dyad clade including Djinga, Dicraeanthus, and Ledermanniella species without stem scales but with pollen dyads. To reduce the polyphyly of Ledermanniella sensu lato (i.e. sensu C. Cusset) we propose restricting Ledermanniella to the species of the former subgenus Ledermanniella, resurrecting Monandriella as monotypic genus, and accepting the genus name Inversodicraea for members of Ledermanniella subg. Phyllosoma