new fern discoveries in Seychelles!
Many Seychellois are familiar with a large fern locally named ‘Baton monsenyer’ commonly growing in the moist mountain forests of the granite islands of Mahé and Silhouette. The Latin name for this species is Angiopteris madagascariensis and it belongs to the fern family Marattiaceae.
Recently two new species of ‘Baton monsenyer’ have been added to the fern flora of Seychelles. Both of them are much rarer and so far have only been found in remote mountain forests of Mahé Island (i.e. are endemic to Mahé).
One of the 2 new ferns is Angiopteris chongsengiana. It has been named in honour of a well-known Seychellois botanist, Lindsay Chong-Seng. Its Creole name is ‘Baton monsenyer-d-gran bwa’. It was first found in 2011, during explorations for the Seychelles National Herbarium (as part of the PCA-Natural History Museum ‘Herbarium Project’). This fern is found in ravines in high mountain forest and is considered to be an Endangered species according to IUCN threat categories.
The other new fern is a rediscovery of a species that was recorded over 100 years ago. It had not been found again and was thought to be a mistaken record - until 2011, when, like the previous species, it was discovered during Herbarium Project explorations. It also belongs to the Marattiaceae family and was previously thought to be Ptisana fraxinea, a species described from Mauritius and supposed to occur throughout tropical Africa. Nevertheless there are significant differences from the Mauritian plant. The Seychelles plant has now been described under the name Ptisana laboudalloniana, thereby honouring Victorin Laboudallon, another well-known Seychellois conservationist. As this species is smaller, it is called ‘Pti baton monsenyer’ in Creole. It is found in similar habitats to Angiopteris chongsengiana and is considered to be a Vulnerable species.
Genetic analysis of the various species of Ptisana was a key input for the revision of this genus for Africa and neighbouring islands. The number of species recognized in the region is now about 9. The closest relative of Ptisana laboudalloniana appears to be a species found on Ascension Island in the Atlantic Ocean (!).
Initial research is showing that there may be other interesting discoveries to be found amongst the new collections of Seychelles’ fern species in the National Herbarium..... PCA will keep you posted!
This work is published in Phytotaxa 158 (1) 057-075 and is the work of Bruno Senterre, Germinal Rouhan, Isabelle Fabre, Charles Morel & Maarten J.M. Christenhusz:
"Revision of the fern family Marattiaceae in the Seychelles with two new species and a discussion of the African Ptisana fraxinea complex."
Bruno and Charles are both PCA members