Begonias are intertropical plants, which means they grow between the Tropic of Cancer, north of the Equator, and its southern neighbour, the Tropic of Capricorn. Most often, the climate of these areas is hot; however, begonias’ habitats are as diverse as the forms of these little-known plants. Yet they have a liking for rugged forest areas.
Most begonias are found in rainforests, where they benefit from high humidity due to abundant rainfall. They are also found along streams or close to waterfalls: for instance in equatorial Africa (Gulf of Guinea, Congo Basin, down to Angola and the Great Lakes in the east), on the eastern coast of Madagascar, throughout South-East Asia (Yunnan, Vietnam, Myanmar, Malaysia, Indonesia, the Philippines), in the montane forests of Borneo and Papua New Guinea as well as in the Mexican forests, throughout Central America and the Guiana Shield (Guyana, French Guiana, Suriname, Venezuela), the North-East of South America (Ecuador, Peru, Colombia) and Brazil (around the Amazon basin, Mata Atlântica). In these areas, begonias are found on the forest litter, as epiphytes, as vines, trailing or climbing-scandent, and most often as rhizomatous plants, frequently lithophytes (growing on rocks, which may be limestone or not). Here there is little or no dry season, and the begonias grow almost continuously.
But some of our favourite plants grow at high elevations (up to 2500 metres) in much sunnier spots; there, they are exposed to a “cool” season in the form of a long, harsh dry period. The begonias found there are very often tuberous (the whole aerial part disappearing during this season), or else shrubby or rhizomatous begonias that shed their leaves during this season, leaving only the stems. Such are the begonias of the Andean foothills of Ecuador, Peru, Bolivia and Argentina, and those of the Himalayan foothills of India, Nepal, Sikkim and China. These plants often grow in rocky areas: the tuber is then firmly attached to the rock or wedged in its crevices, or sometimes, particularly in limestone landscapes, the roots are deeply anchored in rock fissures and only the stems emerge above the scree. Some of these begonias even grow in full sun!
Finally, others are found in “intermediate” areas made up of dry or deciduous* forests (*where the trees shed their leaves during the dry season); these regions are generally much hotter than the equatorial areas. These are the forests of north-western Madagascar, India, central Brazil and South Africa; the begonias growing here also go dormant during the dry season.
All begonias, like many plants, take advantage of the dry season, even a short one, to set fruit and thus produce seeds, as well as to store reserves in their rhizome or tuber.
While some are very broadly distributed (Begonia hirtella for instance, grows almost anywhere in the tropical area, and Begonia oxyloba is found throughout tropical Africa), others have a much more restricted distribution. Some regions, such as Madagascar, show a remarkable level of endemism, with different species being found in neighbouring valleys.
As you may well have guessed, the never-ending deforestation severely impacts begonias, and many species have already disappeared from their habitat.
In order to better understand begonias and their distribution, you will find below a description of their biotopes sorted by continent.
