Senecio namibensis (Asteraceae: Senecioneae), a new species from Namibia

WESSEL SWANEPOEL; ROLF BECKER; VERA DE CAUWER; ABRAHAM E. VAN WYK

doi:10.11646/phytotaxa.571.2.1

Issue: Vol. 571 No. 2: 3 November 2022

Type: Article

Published: 2022-11-03

DOI: 10.11646/phytotaxa.571.2.1

Page range: 103-111

Abstract views: 62

PDF downloaded: 59

Senecio namibensis (Asteraceae: Senecioneae), a new species from Namibia

WESSEL SWANEPOEL⁺⁻
ROLF BECKER⁺⁻
VERA DE CAUWER⁺⁻
ABRAHAM E. VAN WYK⁺⁻

Independent Researcher, P.O. Box 21168, Windhoek, Namibia. H.G.W.J. Schweickerdt Herbarium, Department of Plant and Soil Sciences, University of Pretoria, Pretoria, 0002 South Africa.

Biodiversity Research Centre, Department of Agriculture and Natural Resources Sciences, Namibia University of Science and Technology, Private Bag 13388, Windhoek, Namibia.

H.G.W.J. Schweickerdt Herbarium, Department of Plant and Soil Sciences, University of Pretoria, Pretoria, 0002 South Africa; South African National Biodiversity Institute, Private Bag X101, Pretoria, 0001 South Africa

endemism flora Kaokoveld Centre of Endemism Namib Desert Senecio englerianus Senecio flavus succulent taxonomy Eudicots

PDF (5MB)

Abstract

Senecio namibensis is described as a new species known only from the northern part of the Namib Desert in northwestern Namibia. It is a range-restricted species near-endemic to the Kaokoveld Centre of Endemism. These dwarf shrubs grow on rocky outcrops under harsh desert conditions. Diagnostic characters for Senecio namibensis include the annual or perennial habit, succulent leaves, and radiate capitula with 3–6 yellow ray florets. A comparison of some of the more prominent morphological features to differentiate between S. namibensis and its possible nearest relatives, S. englerianus and S. flavus, is provided. All three species have superficially similar looking succulent leaves, but an obvious difference is that the capitula in S. englerianus are discoid and in S. flavus disciform or obscurely radiate. Based on IUCN Red List categories and criteria, a conservation assessment of Least Concern (LC) is recommended for the new species.

References

Alexander, J.C.M. (1979) Mediterranean species of Senecio sections Senecio and Delphinifolius. Notes from the Royal Botanic Garden Edinburgh 37: 387–428.
Beentje, H. (2016) The Kew plant glossary: an illustrated dictionary of plant terms, 2nd ed. Kew Publishing, Kew, 184 pp.
Coleman, M., Forbes, D.G. & Abbott, R.J. (2001) A new subspecies of Senecio mohavensis (Compositae) reveals Old-New World species disjunction. Edinburgh Journal of Botany 58: 389–403. https://doi.org/10.1017/S0960428601000713
Coleman, M., Liston, A., Kadereit, J.W. & Abbott, R.J. (2003) Repeat intercontinental dispersal and Pleistocene speciation in disjunct Mediterranean and desert Senecio (Asteraceae). American Journal of Botany 90: 1446–1454. https://doi.org/10.3732/ajb.90.10.1446
Decaisne, M.J. (1834) Enumeration des plantes recueillies par M. Bovè dans lex deuxs Arabies, la Palestine, la Syrie et l’Egypte. 2: 5–270.
Drury, D.G. & Watson, L. (1966) A bizarre pappus form in Senecio. Taxon 15: 309–311. https://doi.org/10.2307/1216115
Edwards, D. & Leistner, O.A. (1971) A degree reference system for citing biological records in southern Africa. Mitteilungen der Botanischen Staatssammlung München 10: 501–509. [https://www.biodiversitylibrary.org/page/15185301#page/509/mode/1up]
Funk, V.A., Susanna, A., Stuessy, T.F. & Robinson, H.E. (2009) Classification of Compositae. In: Funk, V.A., Susanna, A., Stuessy, T.F. & Bayer, R.J. (eds.) Systematics, evolution, and biogeography of Compositae. International Association for Plant Taxonomy, Vienna, pp. 171–189.
Germishuizen, G. & Meyer, N.L. (eds.) (2003) Plants of southern Africa: an annotated checklist. Strelitzia 14: 1–1231.
Goudie, A. & Viles, H. (2015) Landscapes and land forms of Namibia. Springer, Dordrecht, 173 pp. https://doi.org/10.1007/978-94-017-8020-9
Hoffmann, O. (1888) Compositae. In: Engler, A. Plantae Marlothianae; ein Beitrag zur Kenntnis der Flora Südafrikas. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 10: 271–282. [https://www.biodiversitylibrary.org/item/684#page/282/mode/1up]
IUCN (2012) IUCN red list categories and criteria: Version 3.1. 2nd ed. Gland, Switzerland and Cambridge U.K., iv + 32 pp.
Jürgens, N., Strohbach, B., Schmiedel, U., Rügheimer, S., Erb, E., Wesuls, D., Schrenk, J., Dreber, N., Schmidt, M., Mayer, C. et al. (2021) Photo guide to plants of southern Africa. Research Unit Biodiversity, Evolution & Ecology (BEE) of Plants, Institute for Plant Science and Microbiology, Hamburg, Germany. Available from: https://www.southernafricanplants.net (accessed 10 December 2021)
Kim, M., Cui, M-L., Cubas, P., Gillies, A., Lee, K., Chapman, M.A., Abbott, R.J. & Coen, E. (2008) Regulatory genes control a key morphological and ecological trait transferred between species. Science 322: 1116–1119. https://doi.org/10.1126/science.1164371
Klaassen, E. & Kwembeya, E. (2013) A checklist of Namibian indigenous and naturalised plants. Occasional Contributions No. 5. National Botanical Research Institute, Windhoek, Namibia, 591 pp.
Linnaeus, C. (1753) Species Plantarum. Vol. 2. Impensis Laurentii Salvii, Stockholm, 640 pp. https://doi.org/10.5962/bhl.title.669
Mendelsohn, J., Jarvis, A., Roberts, C. & Robertson, T. (2002) Atlas of Namibia. Philip, Cape Town, 200 pp.
Milton, J.J. (2009) Phylogenetic analyses and taxonomic studies of Senecioninae: southern African Senecio sect. Senecio. Ph.D. thesis, University of St Andrews, Edinburgh, 50 pp.
Milton, J.J., Affenzeller, M., Abbott, R.J. & Comes, H.P. (2022) Plant speciation in the Namib Desert: potential origin of a widespread derivative species from a narrow endemic. Plant Ecology and Diversity (Preprint available). https://doi.org/10.1080/17550874.2022.2130018
Nordenstam, B. & Pelser, P.B. (2005) Dauresia and Mesogramma: one new and one resurrected genus of the Asteraceae-Senecioneae from southern Africa. Compositae Newsletter 42: 74–88.
Pelser, P.B., Nordenstam, B., Kadereit, W.K. & Watson, L.E. (2007) An ITS phylogeny of tribe Senecioneae (Asteraceae) and a new delimitation of Senecio L. Taxon 56: 1077–1104. https://doi.org/10.2307/25065905
Schultz Bipontinus, C.H. (1845) Senecio. In: Barker-Webb, P. & Berthelot, S. (eds.) Histoire Naturelle des Iles Canaries (Phytographia Canariensis), Vol. 2, part 2, sect. 2. Bureaux, Paris, pp. 316–329.
Seely, M. (2004) The Namib: natural history of an ancient desert. Desert Research Foundation of Namibia, Windhoek, 110 pp.
Thiers, B. (2022) Index Herbariorum: a global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. Available from http://sweetgum.nybg.org/science/ih/ (accessed 22 June 2022)
Van Wyk, A.E. & Smith, G.F. (2001) Regions of floristic endemism in southern Africa: a review with emphasis on succulents. Umdaus Press, Hatfield, Pretoria, 199 pp.