AFRICAN

ORCHIDS

Forest
Afrotemperate forest western cape south africaLow altitude forests provide suitable habitats mainly for epiphytic orchids. Most have small flowers and are therefore difficult to detect. Only a few of the epiphytic species have larger flowers, such as Aerangis species, Cyrtorchis arcuata, Jumellea filicornoides and Angraecum conchiferum. When searching for epiphytic orchids it is sometimes a good idea to look out for their long whitish roots which are attached to the tree bark; these are often more conspicuous than the orchid itself. The commonest epiphytic orchid is Cyrtorchis arcuata which occupies a wide range of different habitats. Many of the epiphytic species are also able to grow lithophytic (i.e. on rocks). A few terrestrial species, such as Corymborkis corymbis, Calanthe sylvatica and some species of Stenoglottis, Disperis and Liparis occur in the undergrowth of subtropical forests. Also the saprophytic Didymoplexis verrucosa occurs here.
Montane forests of the Eastern Cape, KwaZulu-Natal, Swaziland, Mpumalanga and Northern Province are fairly cool but also rich in epiphytic orchids. Their species composition is different from that of the lowland forests although some species occur in both (e.g. Angraecum conchiferum). Small-flowered species of Angraecum, Mystacidium and Polystachya are not uncommon here. Among the terrestrial orchids several species of Disperis grow on the floor of such montane forests (especially D. fanniniae and D. lindley-ana), and also Brownleea coerulea , Holothrix orthoceras, Huttonaea pulchra, H. fimbriata, and Stenoglottis , and Liparis species can be seen occasionally. Liparis bowkeri, Holothrix orthoceras and Stenoglottis species sometimes also grow as low-level epiphytes on tree trunks and on rocks.
Forest margins are often also rich in orchids. They offer good conditions for terrestrial species, mainly because the surrounding vegetation provides shade and some protection from grazing animals. Grassland fires prevent the forest from expanding into the grassland and also remove some of the annual woody growth on the forest margin, and thus make more room for the orchids. In addition, forest margins are also favourable habitats for many epiphytic species.