The Promontory's main slopes are called Quarto Caldo ("Hot quarter", south-facing) and Quarto Freddo ("Cold quarter", north-facing).
The typical, evergreen Mediterranean forest characterises the Quarto Freddo, with evergreen oaks (Quercus ilex) and hop-hornbeams (Ostrya carpinifolia). On this side we also find downy oaks (Quercus pubescens), Italian oaks (Quercus frainetto), and manna ashes (Fraxinus ornus). Shrubs include green olive tree (Phillyrea latifolia), Italian buckthorn (Rhamnus alaternus), tree heath (Erica arborea), strawberry tree (Arbutus unedo), and Spanish broom (Spartium junceum). At the foot of this slope, in a place called Selva Piana, an interesting cork oak wood (Quercus suber) thrives thanks to the protection offered by the Promontory and to the high air humidity.
On the southern slope, Quarto Caldo, sun exposure is high and rainfall scarce, especially in the summer: here, xerophytes grow (plants that have adapted to arid climate), mainly consisting of Mauritania grass (Ampelodesmos mauritanicus), small meadows of annual herbaceous plants, patches of sclerophyll Mediterranean scrub, shrub land, and portions of evergreen oak wood.
The Mediterranean scrub is characterised by mastic (Pistacia lentiscus), myrtle (Myrthus communis), green olive tree (Phillyrea latifolia), Italian buckthorn (Rhamnus alaternus), and climbing shrubs such as wild madder (Rubia peregrina) and Smilax aspera, locally known as "breeches ripper".
The shrub land is very thick and mainly composed of Montpellier cistus (Cistus monspeliensis), heath (Erica multiflora), rosemary (Rosmarino officinalis), and myrtle (Myrtus communis).
On the cliffs there are bushes of tree spurge (Euforbia dendroides), specimens of Mediterranean dwarf palm (Chamaerops humilis) and Centaurea circae, an endemic species.
Halophiles grow on rocky areas by the sea: low bushes of sea-lavender (Limonium circaei), mixed with rock samphire (Crithmum maritimum), and golden samphire (Inula crithmoides), almost reach the water. Near these halophile species there are bushes of Phoenician juniper (Juniperus phoenicea) and hairy spurge flax (Thymelaea hirsuta).
As regards animals, several species of mammals live on the Promontory.
Besides wild boars, there are badgers, weasels, and hazel dormice in the evergreen oak wood of the "cold quarter", and some bat species that find shelter by the caves.
Among birds, it is worth mentioning the rare peregrine falcon, nesting on the cliffs, and some passerines typically found in rocky environments, such as blue rock thrush (nesting), northern wheatear (migratory), wallcreeper (wintering), and black redstart (migratory and wintering).
Among reptiles living in the "cold quarter" we can find the Italian three-toed skink, the four-lined snake, and the asp. Hermann's tortoises, ruin lizards and, among amphibians, green toads live instead in the shrub land.