Monday, March 25, 2024

[Botany • 2024] Voacanga madureirae (Apocynaceae: Tabernaemontaneae) • A New Species from Atlantic Central Africa


Voacanga madureirae  Paiva, O.Lachenaud & Covelo,

in Lachenaud, Paiva, Covelo, Cheek et Onana. 2024. 
photos by Quentin Luke and Maria Do Céu Madureira.

Summary
A new species of Apocynaceae from Atlantic Central Africa, Voacanga madureirae Paiva, O.Lachenaud & Covelo, is mapped, described and illustrated. It occurs on the Gulf of Guinea islands of Príncipe (São Tomé and Príncipe) and Bioko (Equatorial Guinea) and in the highlands of western Cameroon. The new species differs from other African Voacanga by its calyx distinctly exceeding the corolla (vs shorter or at most equalling it). It is further separated from V. chalotiana Pierre ex Stapf by the presence of a row of colleters in the upper half of the calyx (not near the base) and from other Central African species by its syncarpous fruits and almost straight (not strongly twisted) corolla tube. It is assessed as Near Threatened according to IUCN criteria.

Key Words: Bioko, Cameroon, Equatorial Guinea, Gulf of Guinea islands, São Tomé and Príncipe, Tabernaemontaneae.

Voacanga madureirae. A flowers, Q. Luke 13274; B fruit, M. C. Madureira & Equipa Proj. Pagué III 87; C fruit cut in two halves, showing the inside, M. C. Madureira & M. Sebastião 3 MCM.
photos: A Quentin Luke, B – C Maria Do Céu Madureira.

Voacanga madureirae Paiva, O.Lachenaud & Covelo sp. nov. 

RECOGNITION. Voacanga madureirae is easily recognised by its syncarpous fruits, its almost straight (not strongly twisted) corolla tube, and its calyx distinctly exceeding the corolla and bearing inside a dense row of colleters in the upper half of the tube. The first two characters are also found in V. chalotiana Pierre ex Stapf, which, however, has a smaller calyx, bearing a row of colleters near the base and much exceeded by the corolla. All other Central African species of Voacanga have apocarpous fruits, strongly twisted corolla tubes and a corolla usually exceeding the calyx, or equalling it in V. diplochlamys K.Schum., which, however, has puberulous stems and inflorescence while these parts are glabrous in V. madureirae.


 
Olivier Lachenaud, Jorge Paiva, Filipe Covelo, Martin Cheek and Jean Michel Onana. 2024. Voacanga madureirae (Apocynaceae), A New Species from Atlantic Central Africa. Kew Bulletin. DOI: 10.1007/s12225-024-10179-3