African Acanthaceae: diversity and conservation

Taxonomic research into this diverse plant family is helping to inform plant conservation planning in Africa.

Very small white flower

The Acanthaceae (shrimp-plant and acanthus) family is among the most species-rich plant groups in tropical Africa and Madagascar, having diversified in nearly all major habitat types, and displays high numbers of rare and narrow-range species. As such, it has high potential as a proxy for identifying regional centres of plant diversity and conservation priorities across the continent. Until recently, however, it has been largely neglected in taxonomic terms. To address this, Kew has built up expertise in the African Acanthaceae over the past three decades together with a large collections-base in order to advance our knowledge of this important and diverse group.

Taxonomic studies in Africa and Madagascar

Kew has played a leading role in documenting the diversity of African Acanthaceae. A primary focus has been the writing of the Acanthaceae accounts for the Flora of Tropical East Africa (597 species in 50 genera) and Flora Zambesiaca (391 species in 42 genera)

  • Taxonomic research into the species-rich genus Barleria and relatives including a treatment for the new Flora of Namibia programme and detailed studies in Angola and Madagascar.
  • Contributing morphological expertise to phylogenetic studies within the Old World Acanthaceae in order to better understand evolutionary relationships between and within important groups, including the tribes Barlerieae, Justicieae and Ruellieae.

This work is being carried out in collaboration with a range of institutions with expertise and interest in the Acanthaceae, notably Rancho Santa Ana Botanic Garden and University of Colorado in the USA and the National Botanical Research Institute in Namibia.

Atlas of the Acanthaceae of East Africa

This collaboration between the University of Copenhagen, Makerere University, University of Dar es Salaam and Kew aims to apply the extensive herbarium data amassed and the stable taxonomy provided through the FTEA programme, to study plant distribution and diversity patterns in East Africa using the Acanthaceae family as a suitable case study.

The project has amassed about 25,000 georeferenced specimen records to date. Through collaboration with the regional IUCN plant redlist authority, 260 priority taxa of Acanthaceae have been assessed for their conservation status, many being globally threatened.

By mapping the individual species, total species diversity and distribution of the threatened species, this project will enable identification of regional diversity hotspots and plant conservation priorities in East Africa. It will also reveal useful information on biogeographical trends as well as identifying areas that have been under-studied and require further botanical survey. These data will contribute to the identification of Important Plant Areas in Uganda under Kew’s TIPAs programme.


  • To document the diversity and distribution of the Acanthaceae in key regions of Africa and Madagascar.
  • To analyse species distribution data within the family to identify patterns of diversity and endemism and to apply these data to conservation planning initiatives including the Tropical Important Plant Areas (TIPAs) programme.
  • To refine the generic classification of the Acanthaceae family in Africa and Madagascar.

Accelerated Taxonomy

Project Leader

Iain A. Darbyshire

  • Flora accounts of the family in East Africa (FTEA), southern tropical Africa (Flora Zambesiaca) and Namibia.
  • Detailed taxonomic treatments of selected genera, including Barleria in Angola, Namibia and in Madagascar, and publication of discoveries of new species and genera from across the continent.
  • Publication of phylogenetic analyses of critical genera and clades within the Old World Acanthaceae to investigate the evolutionary history of the family.
  • IUCN conservation assessments of over 200 range-restricted species of Acanthaceae from Africa.
  • A published Conservation Atlas of the Acanthaceae of East Africa, highlighting the concentrations of diversity, endemism and threatened species in the region and using these data to identify site-based priorities for conservation and research.
  • Training of colleagues in Africa and Madagascar in the identification of Acanthaceae and in taxonomic methodologies.


  • Natural History Museum of Denmark, University of Copenhagen

East Africa

  • IUCN East African Plants Red List Authority


  • National Herbarium, Addis Ababa University


  • National Herbarium of Namibia, National Botanical Research Institute, Windhoek


  • Botany Dept., University of Dar es Salaam


  • Botany Dept., Makerere University, Kampala


  • Rancho Santa Ana Botanic Garden, California; Museum of Natural History, University of Colorado

Bentham-Moxon Trust, UK

Danish International Development Agency (DANIDA)

Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL) project

Task 060 'Establish and improve baseline inventories for spatial data and biodiversity' – Flora of Namibia Project

Darbyshire, I. (2015)

The genus Hypoestes (Acanthaceae) in Angola

Kew Bulletin 70: 44 (10 pages). DOI 10.1007/S12225-015-9595-4

Darbyshire, I., Vollesen, K. & Ensermu Kelbessa (2015)

Acanthaceae (part II). In: J.R. Timberlake & E.S. Martins (eds.) 

Flora Zambesiaca Vol. 8(6). Royal Botanic Gardens, Kew. 304 pp

Darbyshire, I., Phillipson, P.B. & Rakotonasolo, F. (2014)

Additions to the genus Barleria in Madagascar

Kew Bulletin 69: 9513 (11 pages)

Champluvier, D. & Darbyshire, I. (2012)

Schaueriopsis: a new genus of Acanthaceae (Acanthoideae: Barlerieae) from the Democratic Republic of Congo

Plant Ecology and Evolution 145: 279–284

Darbyshire, I., Vollesen, K. & Ensermu Kelbessa (2010)

Acanthaceae (part II). In: H. Beentje (ed.) 

Flora of Tropical East Africa. Royal Botanic Gardens, Kew. 470 pp

Vollesen, K. (2000)

Blepharis (Acanthaceae)

A taxonomic revision. Royal Botanic Gardens, Kew