African Cyperaceae

Cyperaceae (about 100 genera, 5,500 species) is the third largest monocot family, with around 1,400 species occurring in Africa and Madagascar. Sedges have been the subject of research at Kew for many years and a profound knowledge of this beautiful family has been built up during the past decades. Our research focuses on the biodiversity, evolution and ecology of African Cyperaceae, using a multidisciplinary approach and focusing on a range of genera and geographical areas.

Directing research and conservation where it matters most is critical. Identifying important sites for plant conservation based on assessments of species-richness and levels of endemicity are key to achieve this. The Kew Africa and Madagascar team are active in Kew’s Tropical Important Plant Areas project, focusing on Guinea, Cameroon, Mozambique and Uganda. Cyperaceae can be particularly informative for a site-based conservation approach where wetlands, temporary wet habitats like bowal, high elevation areas and inselbergs are concerned.

Current research of Isabel Larridon is aimed building a framework to investigate evolution if Cyperaceae using targeted sequencing data obtained using the Angiosperm-353 baits developed for Kew’s Plant and Fungal Trees of Life project. One of the characters studied in the family is C4 photosynthesis. Another focus is the Madagascar and Indian Ocean Islands biodiversity hotspot. The origins and diversification of Cyperaceae in Madagascar are currently being investigated.

The largest Cyperaceae genus in Africa is Cyperus with more than 500 species. Species delimitation in Cyperus is often problematic. Currently, Martin Xanthos is trying to resolve the taxonomy of an African species complex characterised by white-glumed spikelets which includes amongst others Cyperus margaritaceus and Cyperus niveus.

Recently, research focused on Cyperaceae tribe Schoeneae. This research resulted in the publication of two new genera to science, one endemic to New Caledonia and the other endemic to the Seychelles, and aided in resolving the very confusing relationships in this group of Cyperaceae. This research also enabled redelimiting the genera Costularia andTetraria. Research into Cyperaceae tribe Abildgaardieae among others resulted in the small African genus Nemum being lumped in the large pantropical genus Bulbostylis.

The genus Scleria (about 250 species), commonly known as nut rushes or razor grasses, has a pantropical distribution and can occasionally be found in (warm) temperate regions. This genus was the topic of a PhD project by Kenneth Bauters at Ghent University under the guidance of Isabel Larridon and David Simpson at Kew. His research resulted in a new infrageneric classification, new species to science, and a taxonomic revision of Scleria subgenus Hypoporum. The Scleria species from Madagascar were studied during a Master project by Javier Galán Díaz at Kew supervised by Isabel Larridon.

Through fieldwork in Africa and Madagascar, data and plant specimens and samples are assembled which are incorporated into Kew’s collections and provide further baseline data and plant material needed for research and conservation purposes.

Objectives

• Avoid the extinction of (near) endemic and threatened Cyperaceae species in Africa and Madagascar through inclusion in the IUCN Red List and in Important Plant Areas.
• Contribute to Kew’s Science Strategy including the Tropical Important Plant Areas and Plant and Fungal Trees of Life projects.
• Construct a new DNA-based classification for the Cyperaceae family at tribal and generic level.
• Build a solid framework to investigate evolution in Cyperaceae.
• Assess the species limits in the Cyperus margaritaceus-Cyperus niveus species complex.
• Investigate generic limits and relationships in Cyperaceae tribes Abildgaardieae and Schoeneae.
• Construct a molecular phylogeny of Scleria and trace evolution of taxonomically important characters to obtain insights into its biodiversity and evolution, and establish a new infrageneric classification for the whole genus.

Department

Identification and Naming

Project Leader

Isabel Larridon

Team

Christina J. Prychid

Martin Xanthos

• Conservation assessments of the (near) endemic and threatened Cyperaceae from Africa and Madagascar.
• A new infrageneric classification of the genus Scleria.
• Molecular phylogenetic study of Costularia s.l.
• Revision of the African and Malagasy species of Costularia.
• Revision of the African Cyperus species with white-glumed spikelets.

International

• Prof. Paul Goetghebeur, Ghent University, Belgium
• Prof. Muthama Muasya, University of Cape Town, Republic of South Africa
• Prof. Marcial Escudero, Universidad de Sevilla, Spain
• Prof. Eric H. Roalson, Washington State University, United States of America
• Prof. Julian R. Starr, University of Ottawa, Canada

B.A. Krukoff Fund For The Study Of African Botany