A review of the fern genus Polystichum (Pteropsida: Dryopteridaceae) in Madagascar and the Mascarene region Jacobus P. ROUX National Botanical Institute, Compton Herbarium, Private Bag X7, Claremont 7735, South Africa.
[email protected] ABSTRACT KEY WORDS The fern genus Polystichum Roth (Dryopteridaceae) in Madagascar and the Polystichum, Mascarene region is reviewed. Eight species are recorded, six being endemic Dryopteridaceae, Madagascar, to the region. Of these four are endemic to Madagascar. The Madagascan Mascarene region. species remain poorly known. RÉSUMÉ Révision du genre Polystichum (Pteropsida: Dryopteridaceae) de Madagascar et des Mascareignes. MOTS CLÉS Révision des fougères de Madagascar et des Mascareignes appartenant au Polystichum, genre Polystichum Roth (Dryopteridaceae). Huit espèces sont retenues, dont Dryopteridaceae, Madagascar, six endémiques de Madagascar. Les espèces malgaches demeurent peu Mascareignes. connues. INTRODUCTION Madagascar has been separated from Africa for at least 100 million years and is well known for its A review of the fern genus Polystichum in high level of endemism. RAVEN & AXELROD Madagascar and the Mascarene region (the (1974) ascribed the rich Madagascan flora to a now Madagascan and Comore archipelagos) is provid- submerged Madagascan plateau that connected it ed. Polystichum is a genus of between 160 (TRYON with India and Antarctica, thus allowing for migra- & TRYON 1982) and 200 species (DAIGOBO tion between these now distant continents until 1972), occurring throughout the temperate parts the late Cretaceous. LEROY (1978), on the other of the world as well as the montane tropics, but is hand, considered the rich Madagascan flora as an mostly absent from the lowland tropics. autochthonous flora that has differentiated princi- ADANSONIA, sér.