The granitic islands of Seychelles are home to about 75 endemic plant species, with a further 25 or so species in the Aldabra group. Particularly well known is the coco de mer, a species of palm that grows only on the islands of Praslin and neighbouring Curieuse. Sometimes nicknamed the "love nut" because the shape of its "double" coconut resembles buttocks, the coco-de-mer produces the world's heaviest seed. The jellyfish tree is to be found in only a few locations on Mahe. This strange and ancient plant in a genus of its own (''Medusagyne'') seems to reproduce only in cultivation and not in the wild. Other unique plant species include Wright's gardenia (''Rothmannia annae'') found only on Aride Island Special Reserve. There are several unique species of orchid on the islands.