By West Equatorial Africa we mean the western part of intertropical Africa on either side of the Equator, from Guinea to northern Angola and along the Congo River. This area has little relief – the main mountain ranges being Mount Nimba (1,850 m) in the west and the Adamawa massif (4,000 m) in Cameroon – and is almost entirely covered by evergreen* rainforest (ombrophilous* forest). Its climate is shaped by the trade wind – north-easterly above the Equator, south-easterly below – which, meeting the oceanic trade wind, forms the clouds that bring rain. It is characterised by:
- Constant heat, around 25°C / 30°C
- Days and nights of almost equal length all year round
- A small temperature range over the year, around 5°C
- Heavy rainfall, over 1,500 mm a year, especially in the mountain forests where it can exceed 8,000 mm; rain falls almost constantly and the dry season is short.
- The result is high humidity*, often above 85%.
Growing conditions for these plants must take these factors into account: these are begonias for the terrarium, delicate and difficult to keep (to find out more, see the section “ Begonia culture« ).
Here are the begonias that grow in these regions, classified by plant “type” and by section.
Plants that are mostly epiphytic* or rupicolous*
- TETRAPHILA : B. subscutata, B. polygonoides, B. gabonensis, B. ebolowensis, B. karperi, B. loranthoides, B. elaeagnifolia, B. longipetiolata, B. squamulosa, B. kisuluana, B. eminii, B. fusialata, B. komoensis, B. capillipes, B. poculifera var. poculifera and B. mannii : from Guinea and Sierra Leone across the whole area (see also East and Southern Africa); epiphytic* plants
- SQUAMIBEGONIA : B. ampla, B. bonus-henricus and B. poculifera var. teusziana : east of the Dahomey Gap, from Nigeria across Central Africa, Uganda, Rwanda, Burundi and the islands of the Gulf of Guinea (see also East and Southern Africa); often epiphytic* or rupicolous* plants
Plants that are mostly terrestrial (growing on the forest floor litter) or rupicolous*, sometimes climbing
- BACCABEGONIA : B. baccata : endemic to São Tomé; terrestrial or rupicolous* plant
- CRISTASEMEN : B. thomeana : São Tomé and Gabon; climbing plant
- FILICIBEGONIA : B. aspleniifolia, B. minutifolia, B. elatostemmoides, B. auriculata, B. macrocarpa, B. sciaphila, B. sessilifolia and B. gossweileri : from Guinea to eastern Congo and south into Angola; terrestrial plants
- MEZIEREA : B. oxyloba : the whole of tropical Africa (with other species from Madagascar, the Seychelles, the Comoros and the Mascarenes); terrestrial plant, rarely epiphytic* or saxicolous*
- SEXALARIA : B. annobonensis : coast of Cameroon, the islands of São Tomé, Príncipe and Annobón; terrestrial or rupicolous* plant
The next two sections are those of the yellow-flowered begonias, which are small terrestrial, rhizomatous plants, sometimes epiphytic*.
(Note that some species in these sections have white or pink flowers)
- LOASIBEGONIA : B. adpressa, B. atroglandulosa, B. duncan-thomasii, B. heterochroma, B. letouzeyi, B. microsperma, B. minuta, B. potamophila, B. prismatocarpa, B. pseudoviola, B. pulcherrima, B. quadrialata, B. salisburyana, B. scapigera, B. schaeferi, B. scutifolia and B. staudtii : from Guinea to eastern Zaire, Rwanda, Burundi, Angola.
- SCUTOBEGONIA : B. aggeloptera, B. anisosepala, B. ciliobracteata, B. clypeifolia, B. dewildei, B. erectocaulis, B. erectotricha, B. ferramica, B. hirsutula, B. lacunosa, B. laporteifolia, B. mbangaensis, B. mildbraedii, B. peperomioides, B. scutulum, B. susaniae, B. vankerchklovenii, B. vittariifolia, B. wilksii, B. zairensis and B. zenkeriana : from Côte d’Ivoire to eastern Zaire and the Congo/Angola border
