Epiphytic as well as terrestrial orchids grow on mainland Africa and on the islands of Indian Ocean. However, the occurrence of epiphytes and terrestrials depends upon the climatic conditions of that particular region. Epiphytes are more abundant in tropical Africa, while terrestrials dominate the temperate regions.

There are 105 orchid genera, with some 3545 species inhabiting the African continent. African orchids generally bear white coloured flowers. Some of these African orchid species are listed below. These orchid species have been grouped under two categories: transcontinental and endemic.

• Transcontinental species:
Apart from the African continent, the transcontinental orchid species are also found in other continents. Such orchid species exhibit the ability to survive a wide range of climatic as well as other conditions. So you can try out these species for your garden.
1. Bulbophyllum longiflorum grows not only on the African continent, but is also found growing in South Asian region, Australia and the Pacific Oceans islands.
2. Eulophia orchids occur in nearly all continents. Some are epiphytes, some terrestrial, and are even seen growing on rocks. These can be grown for foliage as well as for beautiful inflorescence.
3. The terrestrials Oeceoclades are mostly confined to Africa, except O. maculata (aka African Spotted Orchid or Monk Orchid) which has established itself across the America continent (both North and South). Though, it does not have beautiful flowers but it is blessed with attractive foliage, having mottled leaves like the Jewel Orchids (Paphiopedilums).

• Species Endemic to Africa
These orchid species are found in different regions of Africa only.
1. Aerangis is an epiphytic orchid genus, with mostly fragrant flowers. A. calanthe has beautiful large white flowers.
2. Ansellia africana (aka African ansellia or the leopard orchid) is found in the tropical Africa. It is an epiphyte with beautiful flowers. There are a lot of variants of this orchid in nature.
3. Angraecum are epiphytes with beautiful fragrant flowers, preferring cooler temperatures. Along with attractive foliage A. aporoides also bears tiny scented flowers. Orchids like A. campactum, A. dendrobiopsis, A. didieri have large and scented flowers.
4. Nearly all Bulbohyllum species encountered in Africa are endemic. Though not known for their flowers, orchids like B. comatum, B. subligaculiferum, B. schinzianum, B. vanum, B. winklerii have somewhat conspicuous flowers.
5. Bonateas are terrestrial orchids, and only species under cultivation is B. speciosa. This orchid has beautiful flowers and is reportedly easy to cultivate.
6. Ceratandra is a terrestrial orchid genus. C. grandiflora has variants having white, yellow to reddish yellow coloured flowers.
7. Cynorkis are small sized orchids with terrestrial habit. Some of the species of this group have large flowers,like C. spatulata which can be grown as a miniature orchids. Large flowers of C. calanthoides make it an attractive option for home gardens. C. fastigiata has somewhat conspicuous flowers.
8. Cyrtorchis an epiphytic genus, which grows in warm and humid climate and mostly bears whitish flowers. C. chailluana, C. monteiroae have large fragrant flowers.
9. Eurychone rothschildiana is an epiphyte, which looks like a Phalaenopsis. It prefers warm conditions and produces beautiful flowers.
10. Some Habenaria orchids found in Africa have beautiful flowers, e.g. H. walleri and H. villosa. But most have beautiful foliage.
11. Jumellea is an epiphytic group of orchids, growing in warm humid climates and bearing mostly white coloured flowers. J. fragrans and J. major have large scented flowers.
12. Mystacidium is a small genus of approximately 10 epiphytic species. M. venosum is endemic to Southern Africa. It is an epiphyte, having scented white flowers.
13. Herschelias are endemic to Southern and South-Central Africa. These are terrestrial orchid, with several rare species of which some 16 species have been identified so far.
14. Disa is a well-known and terrestrial orchid genus of South African, having 90 known species. The genus has beautiful red to pink coloured flowers.
15. Polystachyas are tropical epiphytes and are found all over the world, like the bulbophyllums. P. bella has a beautiful inflorescence.
16. Pterygodium is a terrestrial genus in which flowering is stimulated in some species after fire burns down the area where they were growing previously (also seen in Disas). Like Disas, these are also difficult to grow under cultivation.
17. Rangaeris epiphytic orchids do not have very attractive flowers but some species produce fragrant flowers (R. amanuensis and R. musciola).
18. The terrestrial orchids of Satyrium genus have showy flowers. Mostly confined to South Africa, the orchids S. acuminatum, S. bicallosum and S. bicorne produce beautiful fragrant flowers.
19. Sobennikoffias are confined to Madagacar and are epiphytic in habit. S. humbertiana is stated to produce fragrant flowers.
20. Stenoglottis is a terrestrial/lithophytic genus. It grows in mist filled surroundings and nearly all species have beautifully spotted small flowers, bunched together in dense inflorescences.

Sources
1. Vermeulen, J. J. Orchid Monographs: A Taxonomic Revision of the Continental African Bulbophyllinae.
2. Jay's Internet orchid species photo encyclopedia.