Plant Ecology and Evolution 154(3): 483-496, doi: 10.5091/plecevo.2021.1823
Taxonomic description and pollination ecology of Cyrtorchis okuensis (Orchidaceae, Angraecinae), a new species endemic to the Cameroon Volcanic Line
expand article infoLaura N. Azandi‡, Tariq Stévart§|, Bonaventure Sonké#, Murielle Simo-Droissart, Tania D’haijère¤, Vincent Droissart«
‡ Plant Systematics and Ecology Laboratory, Higher Teachers’ Training College, University of Yaoundé I, Yaoundé, Cameroon§ 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¤ Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, Brussels, Belgium« Institut de Recherche pour le Développement, Montpellier, France

Corresponding author: Laura Azandi ( lazandingnintedem@yahoo.fr )

© Laura N. Azandi, Tariq Stévart, Bonaventure Sonké, Murielle Simo-Droissart, Tania D’haijère, Vincent Droissart.
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: Azandi LN, Stévart T, Sonké B, Simo-Droissart M, D’haijère T, Droissart V (2021) Taxonomic description and pollination ecology of Cyrtorchis okuensis (Orchidaceae, Angraecinae), a new species endemic to the Cameroon Volcanic Line. Plant Ecology and Evolution 154(3): 483-496. https://doi.org/10.5091/plecevo.2021.1823
Open Access
Abstract

Background and aims – A recent taxonomic and molecular study of the genus Cyrtorchis revealed three new species. Here, we describe one of these new species, endemic to the Cameroon Volcanic Line (CVL), and compare it to its closest relatives. Its conservation status is provided along with detailed information on its ecology and reproductive biology.

Material and methods – A detailed examination of 21 herbarium specimens was performed using standard practices of herbarium taxonomy. The conservation status of the new species was assessed using the IUCN Red List Categories and Criteria. Furthermore, we investigated the reproductive biology of the new species in an easily accessible subpopulation in Cameroon and tested the hypothesis of hawkmoth pollination in the genus Cyrtorchis.

Key results – The newly discovered species, here named C. okuensis, is restricted to the montane forest (1600 to 2500 m elevation) of the CVL and is currently assessed as Near Threatened (NT). Among angraecoid orchids in which hawkmoth pollination is recorded (~16 species), C. okuensis has the shortest nectar spur (19–40 mm). In situ observations revealed hawkmoths with short proboscis of the genus Hippotion (H. celerio, H. eson, and H. osiris) as the main pollinators. The rate of pollination and fruiting under natural conditions was low and among the 448 surveyed flowers only 38.8% (174/448 flowers) had their pollinia removed, 19% produced fruits (87/448 flowers), and 16% (70/448 flowers) set mature fruits.

Conclusion – Cyrtorchis okuensis is clearly differentiated from C. submontana by its longer and wider floral bracts, longer anther caps, and wider triangular dorsal sepal.

Keywords
angraecoid orchids, epiphyte, hawkmoth, IUCN Red List Categories and Criteria, pollination, systematics

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