A taxonomic synopsis of unifoliolate continental African<i>Vepris</i>(Rutaceae) with three new threatened forest tree species from Kenya and Tanzania

2022

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A new subgenus, Subg. Disticha is erected for 14 species of simple-leaved Cola sharing unique characters within the genus which are presumed synapomorphies: distichous phyllotaxy; petioles lacking pulvini; petioles of uniformly short length, <10 mm long; male flowers with short androphores <1(- 2) mm long; stamens 4 - 5; stem indumentum where present, dominated by short simple translucent hairs (except in C. philipi-jonesii where stellate), and in many species dark purple to black stems with contrasting bright white lenticels. All species have fruit with small globose, unsculptured orange mericarps c. 1 cm diam. (where fruits are known). The species of this subgenus range from SE Nigeria in the west to coastal Kenya and Tanzania in the east and Malawi in the south, but are absent from the Congo basin. Species diversity is highest in the Cross-Sanaga and Eastern Arc-Coastal Forest biogeographic areas, consistent with these taxa being Pleistocene refuge species. The species are mainly monoecious, but dioecy cannot yet be ruled out in some species. In two species where sufficient material was available for investigation (Cola chlorantha, C. roy), the simple cymes were found to be bisexual, the terminal flower being female, the two lateral flowers often being male, a pattern previously unreported in the genus. All species are understorey shrubs or small trees of evergreen lowland or submontane forest, except C. uloloma of coastal semi-deciduous forest in E Africa and which is unique in showing xerophilic characteristics. The species can be divided into group A: five species mainly in E Africa with rapidly glabrescent or glabrous stems, conspicuously asymmetric leaves, few-flowered, pedunculate cymes (C. uloloma, C. chlorantha, C. roy sp.nov., C.udzungwa, C. asymmetrica sp. nov.); group B: in Lower Guinea (Atlantic coast of Africa) with hairy stems, symmetric or inconspicuously asymmetric leaves, sessile, fasciculate inflorescences: (Cola mayimbensis, C. philipi-jonesii, C. metallica, C.moussavoui, C. stigmatosa, C. takamanda sp.nov. C. toyota sp. nov, C. campo-maan, C. zanaga sp. nov.). Of the seven new species to science, two are named informally since the material is so incomplete (sterile), and five are formally named. Species diversity is highest in Cameroon and Tanzania, each with four species, followed by Gabon with three species. It is expected that additional new species will be found in poorly-surveyed surviving evergreen forest habitat in each of these three countries. Conservation assessments are given for each species using the IUCN 2012 standard. All species are considered threatened, with ten species being Critically Endangered (the highest category of threat), each known from a single location, with their forest habitat threatened mainly by clearance for agriculture.

Section: Taxonomic Resultsmentioning

confidence: 99%

Section: Taxonomic Resultsmentioning

confidence: 99%

Section: Taxonomic Resultsmentioning

confidence: 99%

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Cola Subgenus Disticha subg. nov. (Malvaceae-Sterculiaceae) of tropical Africa, a synoptic taxonomic revision with seven new species

2022

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“…2017; 2022a)) to East (e.g. Kihansia lovettii Cheek and Vepris sp A of FTEA in Tanzania (Cheek 2004; Cheek & Luke 2022)).…”

Section: Discussionmentioning

confidence: 99%

“…Inversodicraea pygmaea G. Taylor and Saxicolella deniseae Cheek in Guinea(Cheek et al 2017;2022a)) to East (e.g. Kihansia lovettii Cheek and Vepris sp A of FTEA in Tanzania(Cheek 2004;Cheek & Luke 2022)).…”

mentioning

confidence: 99%

A new Critically Endangered cloud forest tree Microcos (Grewiaceae-Malvaceae) from the Rumpi Hills of S.W. Region Cameroon

Edwards

Onana

2022

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Summary. We describe Microcos rumpi (Grewiaceae-Malvaceae) as a new species to science from the Rumpi Hills of SW Region Cameroon, a proposed Tropical Important Plant Area. Confined on current evidence to submontane forest, the species is threatened by expanding habitat clearance for farms and is assessed as Critically Endangered. A massive tree, attaining 35 - 40 m height, and 80 cm trunk diameter at 1.3 m above ground, its biomass is calculated as in the range of 7 - 8 metric tonnes. It is the third tree species of the genus recorded from Cameroon and only the fourth recorded west of D.R. Congo. A key to these four species is presented. The concept of Microcos in Africa in relation to Grewia is discussed, and three new combinations are made, transferring three species names from Grewia to Microcos: Microcos louisii (Wilczek) Cheek, M. evrardii( Wilczek) Cheek and M.schmitzii (Wilczek) Cheek.

Chemotaxonomy supports morphology in the identification of Vepris hemp (Rutaceae) a new species of Critically Endangered deciduous forest shrub from Usambara Mts, Tanzania

Langat

Hemp

2022

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Hemp 7152, a sterile herbarium plot voucher of a shrub from a rare type of deciduous forest in the Usambara Mts, Tanzania was tentatively identified using morphology as a new species of Vepris (Rutaceae). To gain further support for its placement its chemistry was investigated. The compounds isolated from Hemp 7152 were four quinoline alkaloids, kokusaginine (1), N-methylplaty-desminium ion (9), ribalinium ion (10), and isoplatydesmine (11), and seven acridone alkaloids, arborinine (2) 1,2,3-trimethoxy-N-methylacridone (3), 1,2,3,5-tetramethoxy-N-methylacridone (4), 1,3-dimethoxy-N-methylacridone (5) and toddaliopsis A (6), evoxanthine (7) and tecleanthine (8). In addition, lupeol and ferulic acid were isolated from this plant. The combination of quinoline and acridone alkaloids is restricted to the Rutaceae family, confirming beyond reasonable doubt the placement of this material in the Rutaceae. Within Rutaceae in tropical Africa, only the genus Vepris is unarmed, with trifoliolate leaves. Using an identification key, and herbarium specimen matching, Hemp 7152 was morphologically placed as close to Vepris uguenensis, sharing xerophytic characters unusual in the genus. The species are geographically close, occurring in adjoining mountains in northern Tanzania. However, Vepris uguenensis contains 13 alkaloids which are not present in Hemp 7152, nor in any other species of Vepris that has been studied, supporting species recognition for Hemp 7152 which is formally named as Vepris hemp, morphologically characterised, illustrated and assessed as Critically Endangered using the IUCN 2012 standard. The new species appears restricted to an almost extinct type of deciduous forest, characterised in this paper.