@article{c9dd9a13eec14b47a2561eb981dae4e8,
title = "Reinstatement of the name Petalidium ovatum (Acanthaceae), with an amplified description of the species",
abstract = "The name Petalidium ovatum is reinstated and an amplified description is provided for a species of Petalidium confined to Namibia. Petalidium ovatum used to be treated as a synonym of the widespread P. englerianum, but morphological characters support the reinstatement. Petalidium ovatum is a range-restricted species, only known from the Khorixas-Bergsig area in the Kaokoveld Centre of Endemism, northwestern Namibia, where it grows on arid hillsides and along ephemeral riverbeds and drainage lines. Diagnostic characters for P. ovatum include the pale grey, often almost white, appearance of the plants, vegetative parts with a dense white indumentum of both stellate and dendritic trichomes, flowers borne in short few-flowered dichasia, bracts oblanceolate with apices acute or obtuse, and bracteoles widely ovate. The flowers of P. ovatum are distinctive in having the anterior corolla lobe partly or completely yellow, the others burgundy, and with the two upper lobes connate towards the base for almost half their length. A comparison of some of the more prominent morphological features to differentiate Petalidium ovatum from P. englerianum, its morphologically most similar relative, is provided. Based on IUCN Red List categories and criteria, a conservation assessment of Least Concern (LC) is recommended for the reinstated species.",
keywords = "Bergsig, Kaokoveld, Kaokoveld Centre of Endemism, Khorixas, Kunene Region, Ruellieae, desert, endemism, flora, lectotypification, taxonomy",
author = "Wessel Swanepoel and Dexter, \{Kyle G.\} and Oriane Loiseau and Wyk, \{Abraham e. van\}",
note = "Funding Information: We would like to thank Dr Hester Steyn, South African National Biodiversity Institute, for help in preparing the distribution map and the list of specimens examined. The curator and staff of the National Herbarium of Namibia (WIND), South African National Biodiversity Institute, Pretoria (PRE), and Royal Botanic Garden Edinburgh (E) are thanked for their assistance during visits to the herbaria. Our grateful thanks to Dr Reto Nyffeler, curator of vascular plants at Herb. Z+ZT, for providing specimen images, and to Prof. Peter Linder and Dr Colin Hughes, both from Z{\"u}rich, for valuable observations on specific herbarium specimens in Z+ZT. The first author is especially grateful to his wife Hannelie for assistance and support during field trips and to Ansie Bosman from Wilderness Safaris for referring to him the request for identification of the species here reinstated as Petalidium ovatum. The constructive comments of two anonymous reviewers are greatly appreciated. AEvW and WS gratefully acknowledge the University of Pretoria for financial and institutional support, and OL acknowledges with thanks funding from the Swiss National Science Foundation (P2LAP3\_191377 and P500PB\_203081). KGD and OL are grateful to the National Commission on Research, Science and Technology of Namibia for authorisation to conduct research on Petalidium in Namibia (RPIV15022022). Publisher Copyright: Copyright {\textcopyright} 2023 Magnolia Press.",
year = "2023",
month = nov,
day = "23",
doi = "10.11646/phytotaxa.626.3.2",
language = "English",
volume = "626",
pages = "159--169",
journal = "Phytotaxa",
issn = "1179-3155",
publisher = "Magnolia Press",
number = "3",
}