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Posted: 3/30/2012 | Print Friendly Version

Missouri Botanical Garden Botanist Aided Identification
of the Critically Endangered Species

Erythrina schliebenii 2(ST. LOUIS): Scientists have confirmed the rediscovery of two tree species that were twice feared to have become extinct, according to a report recently published in the Journal of East African Natural History1. The finds were made in highly threatened fragments of dry coastal forest in Tanzania.

Botanist Roy Gereau of the Africa and Madagascar Department at the Missouri Botanical Garden is a member of the East African Plant Red List Authority and coordinates the collection of data for International Union for Conservation of Nature (IUCN) Red List assessments in East Africa. Beginning in 2009, he worked with British scientist Phil Clarke to confirm and correct identifications of specimens from southeastern Tanzania to determine the current status of these species.

“Both trees are still in critical danger of extinction, given that fewer than 50 individuals of each species are known,” said Assistant Curator and Tanzania Program Director Gereau. “‘Critically Endangered’ is the highest threat category on the IUCN Red List of Threatened Species, and any species with fewer than 50 mature individuals surviving in the wild is automatically placed in that category.”

Erythrina schliebenii 1One of the tree species, Erythrina schliebenii (in the legume family, Fabaceae) belongs to the genus of “coral trees” which have spectacular red flowers and viciously spiny trunks. The tree was only known from two collections from the 1930s, in an area later cleared for a cashew nut plantation, and was listed as “Extinct” on the IUCN Red List in 1998. It was, however, recollected in a small patch of unprotected forest in 2001, but when a part of that forest was cleared for a biofuel plantation in 2008 it was again feared that it might have gone extinct. The other tree species, Karomia gigas (in the mint family, Lamiaceae), was only known from a single specimen cut down a few years after it was first discovered in coastal Kenya in 1977. Another tree was found in 1993 some 600 kilometers away in a tiny fragment of forest in Tanzania, but a more recent search at the same site was unable to relocate it.

Last year botanists from the University of Dar es Salaam, Tanzania set out to look for both trees near where they had most recently been found. They discovered small populations of both in remote coastal forest near Kilwa in southeastern Tanzania.

The coral tree Erythrina schliebenii was collected with mature seeds for the first time, allowing taxonomists at the Royal Botanic Gardens, Kew to remove previous doubts of its status as a distinct species. This was possible through consulting reference collections of coral tree specimens housed in herbaria throughout the world, including specimens of related African species in the Missouri Botanical Garden herbarium.

Recent improvements in infrastructure, together with a rapid population increase, are putting the coastal forests of southeastern Tanzania under increasing threat of being degraded and cleared.

Cosmas Mlig with Karomia gigas leaf and twigErythrina schliebenii has only survived because it grows in rocky areas that are not usually cleared for cultivation, but even those areas will be cleared one day if nothing is done,” said botanist Cosmas Mligo from the University of Dar es Salaam.

The discovery of these rare trees will spur efforts by the World Wildlife Fund (WWF), in partnership with local communities and the Tanzanian government, to conserve the patches of coastal forest where they were found.

Recent fieldwork in Tanzania’s coastal forests was supported by the United Nations Development Programme Global Environment Facility (UNDP GEF), the WWF and the Tanzania Forest Service.

Today, 153 years after opening, the Missouri Botanical Garden is a National Historic Landmark and a center for science, conservation, education and horticultural display. With scientists working in 35 countries on six continents around the globe, the Missouri Botanical Garden has one of the three largest plant science programs in the world and a mission “to discover and share knowledge about plants and their environment in order to preserve and enrich life.” For general information about the Missouri Botanical Garden, visit

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1 Paper citation: Clarke, G.P., N.D. Burgess, F.M. Mbago, C. Mligo, B. Mackinder & R.E. Gereau. 2011. Two ‘extinct’ trees rediscovered near Kilwa, Tanzania. J. East African Nat. Hist. 100(1&2):133–140.