Included here is the Congo Basin region including eastern Nigeria, eastern Cameroon and the islands of the Gulf of Guinea (Fernando Po, Principe, Sae Tome and Annobon).

Congolian Sub-Montane Forest

Also known as cloud, moss and elfin forest these occur at altitudes ranging from 800-1900 m where average tree height is just 3 m. Species composition varies somewhat with altitude but in the Kupe, Mwanenguba and Bakossi mountains common tree species typically include Allanblackia gobonensis, Chionanthus africanus, the tree fern Cyathea manniana, Dasylepis racemosa, Garcinia smeathmannii, Pentadesma grandifolia, Polyscias fulva, Pseudagrostistachya african, Quassia sanguinea and endemic species such as Cyclicomorpha solmsii (Caricaceae), Macaranga occidentalis (Euphorbiaceae), Oncoba lophocarpa (Saliacaceae) and Rhaptopetalum geophylax (Lecythidaceae). Typical shrub layer species are Psychotria peduncularis, Sorindeia grandifolia and the endemic Coffea montekupensis (Rubiaceae), Myrianthus preussii subsp. preussii (Cecropiaceae) and Pauridiantha paucinervis (Rubiaceae). Among the terrestrial herbs are Buforrestia mannii, Cardamine trichocarpa, Polyspatha paniculata, Sanicula elata and the endemic Graptophyllum glandulosum (Acanthaceae). The herb layer is also characterized by many saprophytic species. In fact, the montane forests of Mount Kupe and the Bakossi Mountains possibly support the most diverse assemblage of vascular saprophytes on the planet and several, such as Afrothismia pachyantha (Burmanniaceae) and Kupea martinetugei (Truridaceae), are endemic to these mountains. Likewise the epiphytic flora is also extremely diverse and possibly the richest in Africa. In addition to the more typical epiphytic groups (mainly pteridophytes and orchids), taxa from many other families are represented including Anthocleista scandens (Loganiaceae), Chassalia petitiana (Rubiaceae), Dorstenia astyanactis (Moraceae), Procris crenata (Urticaceae), Rhipsalis baccifera (Cactaceae), Utricularia mannii (Lentibulariaceae) and the endemic Begonia duncan-thomasii (Begoniaceae), Bulbostylis densa var. cameroonensis (Cyperaceae) and Preussiella kamerunensis (Melastomataceae). Certain species of Schlefflera and many species of Ficus begin life as epiphytic shrubs but later become terrestrial trees through the “strangler” procedure. Lianas are well represented with species such as Jasminum bakeri, Pararistolochia ceropegioides and Uvaria heterotricha.

Congolian Montane Forest

These forests are characteristic of uplands ranging in elevation from 2000-2050 m and can be found, for example, on the Mwanenguba caldera and Mount Kupe. Their canopies rarely exceed about 8 m and typically include Bersama abyssinica, Cassipourea malosana, Carapa grandiflora, Clausena anisata, Ilex mitis, Olea capensis, Podocarpus milanjianus, Prunus africana, Schefflera abyssinca and the endemic Ixora foliosa (Rubiaceae), Schefflera mannii (Araliaceae) and Syzygium staudtii (Myrtaceae). The main understorey shrubs are Cassine aethiopica, Discopodium penninervium, Maytenus buchananii, Rhamnus prinoides, Xymalos monospora and the endemic Batesanthus purpureus (Asclepiadaceae), Pavettia hookeriana, P. kupensis (Rubiaceae) and Psydrax dunlapii (Rubiaceae). Lianas include Clematis simense, Embelia schimperi, Jasminium preussii, Stephania abyssinica and the endemic Dalbergia oligophylla (Fabaceae) and Embelia mildbraedii (Myrsinaceae). Some of the main herbs are Mimulopsis solmii and the endemic Acanthopale decempedalis (Acanthaceae), Brachystephanus giganteus, B. kupensis (Acanthaceae), Oreacanthus mannii (Acanthaceae) and Plectranthus insignis (Lamiaceae). There is some evidence to suggest that a number of under storey herbs undergo synchronous mass flowering.

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