Plant Ecology and Evolution 153(2): 257-266, doi: 10.5091/plecevo.2020.1670
Three new species of Tricalysia (Rubiaceae) from Atlantic Central Africa
expand article infoOlivier Lachenaud‡, Tariq Stévart§|, Bonaventure Sonké#
‡ Meise Botanic Garden, Meise, Belgium§ Missouri Botanical Garden / Université Libre de Bruxelles, Brussels, Belgium| Missouri Botanical Garden, Africa & Madagascar Department, St. Louis, United States of America¶ University of Yaoundé I, Yaoundé, Cameroon# University of Yaoundé I, Ecole Normale Supérieure, Yoaundé, Cameroon

Corresponding author: Olivier Lachenaud ( olivier.lachenaud@meisebotanicgarden.be )

© Olivier Lachenaud, Tariq Stévart, Bonaventure Sonké.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Lachenaud O, Stévart T, Sonké B (2020) Three new species of Tricalysia (Rubiaceae) from Atlantic Central Africa. Plant Ecology and Evolution 153(2): 257-266. https://doi.org/10.5091/plecevo.2020.1670
Open Access
Abstract

Background and aims – The genus Tricalysia A.Rich. (Rubiaceae), regarded here in the strict sense (i.e., excluding Empogona Hook.f.), includes 77 species in tropical Africa, Madagascar and the Comoros. In the current paper, three new species from Atlantic Central Africa are described and illustrated; their conservation status is also assessed.

Material and methods – This paper is based on a study of herbarium collections from BR, BRLU, K, LBV, P, WAG and YA. Normal practices of herbarium taxonomy have been applied. The conservation status assessments follow the IUCN Red List criteria.

Results – Tricalysia lophocarpa O.Lachenaud & Sonké is endemic to Gabon and is best recognised by its fruits with 8–10 narrow longitudinal ribs. Tricalysia obovata O.Lachenaud & Sonké is endemic to Equatorial Guinea (Rio Muni) and may be recognised by its obovate leaves with rounded base, glabrous stems, and sessile flowers with included style and half-exserted anthers. Tricalysia wilksii O.Lachenaud & Sonké occurs in Gabon and southwestern Republic of Congo, and may be recognised by its glabrous stems and leaves, the latter with crypt domatia, its linear calyx teeth equalling or exceeding the tube in length, and its shortly pedicellate fruits. The three species are assessed respectively as Near-threatened (T. lophocarpa), Critically Endangered (T. obovata) and Vulnerable (T. wilksii).

Keywords
Tricalysia, Rubiaceae, Coffeeae, new species, taxonomy, Central Africa, Gabon, Equatorial Guinea, Republic of Congo

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