Land within the national park is characterised by steep terrain covered with dense secondary forest and shrub woodland, punctuated by cliffs and large granite boulders. Above 600 m elevation there are remnant stands of primary forest with few exotics. Endemic species include the very rare Medusagyne oppositifolia and Vateriopsis seychellarum, the commoner Dillenia ferruginea and Northea hornei, as well as Phoenicophorium borsigianum, Nephrosperma vanhoutteanum, Erythroxylum sechellarum, Nepenthes pervillei and Secamone schimperianus.
Outside the national park includes the mountainous area to the south-east as well as the adjacent districts of La Misère and Cascade. The latter contain much anthropogenic habitat, such as orchards, small farms, tea plantations, housing, roads and other infrastructure.