of the Moka District about a century ago; these reptiles are considered to be aggressive and are fast invading other rivers of the island. Marine life Butterflies About 39 butterfly species are known from Mauritius and Rodrigues. Seven of these are endemic. Molluscs Flora Indigenous flora Over 700 native species of flowering plant are found in Mauritius and nearly half of these (246) are endemic. Rainforest formerly covered most of the island with palm savannah in drier regions and areas of heathland in the mountains. Most of this natural vegetation has been destroyed and what remains is threatened by the spread of introduced plants. Native trees include eleven surviving species of Mauritius ebony (Diospyros tesselaria, Diospyros egrettarum, Diospyros revaughanii, Diospyros melanida, Diospyros leucomelas and several others), takamaka (Calophyllum tacamahaca), manglier vert (Sideroxylon cinereum), manglier rouge (Sideroxylon puberulum), ox tree (Polyscias maraisiana), bois de natte (Labourdonnaisia species) and a range of other indigenous and endemic tree species. The palm species that are indigenous to the island of Mauritius are Acanthophoenix rubra (possibly other species), Dictyosperma album (var. album & conjugatum), Hyophorbe amaricaulis, Hyophorbe lagenicaulis, Hyophorbe vaughanii, Latania loddigesii and Tectiphiala ferox. Mauritius is the home of a large number of endemic species of Pandanus (screwpine or vacoas), namely: Pandanus carmichaelii, Pandanus barkleyi, Pandanus conglomeratus, Pandanus drupaceus, Pandanus eydouxia, Pandanus glaucocephalus, Pandanus iceryi, Pandanus incertus, Pandanus macrostigma, Pandanus microcarpus, Pandanus obsoletus, Pandanus palustris, Pandanus prostratus, Pandanus pseudomontanus, Pandanus pyramidalis, Pandanus rigidifolius, Pandanus sphaeroides, Pandanus spathulatus, Pandanus vandermeeschii and Pandanus wiehei. The common vacoas sac (Pandanus utilis) of Madagascar has also been introduced and propagated in Mauritius, and it has now naturalised. The national flower of Mauritius is Trochetia boutoniana or "boucle d'oreille" which is now restricted to a single mountain. Introduced and invasive plants Introduced plants that have become invasive include "Chinese" (actually Brazilian) guava (Psidium littorale), travellers trees (Ravenala) and Lantana camara. For the purpose of landscaping and gardening in Mauritius, exotics have traditionally been used, and many of these have spread into the surrounding vegetation. Bougainvillea (Bougainvillea glabra) and frangipani (Plumeria alba) are still among the most commonly planted ornamental species. However, for urban and roadside landscaping Mauritius is beginning to turn to their many varied and unique endemic plant species. Many endemic species, such as bottle palms and ox tree, are now being used as ornamentals for both public landscaping and in private gardens across Mauritius. Conservation Conservation work