We were recently privileged to revisit some of the caulescens habitats, and as always, the escarpment is also a major attraction. At 1700-2000 m it overlooks to the east the Lowveld at 500-700m.

The map below gives the major features. South Africa's borders with Botswana, Zimbabwe, Mocambique and Swaziland are shown (top/right).

Urban centres are indicated with squares. Major cities are Pretoria and Johannesburg (bottom left).

The two most important roads are, in this case:

1. The North Road (remember Rhode’s plan for a Great North Road from the Cape to Cairo?) past Pietersburg, Louis Trichardt and Messina to Zimbabwe, and

2. The East Road through Nelspruit to Mocambique.

The topography from west to east consists of the Highveld at 1.500+m rising slowly to the high rainfall (as much as 3.000 mm pa) escarpment at up to 2.000m in the east. The escarpment runs N:S just west of the foothill towns of Tzaneen and Nelspruit, continuing south through Swaziland and Natal into the Cape. Graskop is at the edge of the escarpment. The Soutpansberg (Salt Lake Mountains) are the northernmost mountains in South Africa, running east-west just north of the Tropic of Capricorn and with the town of Louis Trichardt at the foot of the pass north. East of the escarpment is the lowveld at 400-600m. Dry and very hot in summer (at times over 40 C), with low rainfall (under 500 mm pa), it contains the famous Kruger National Park.

Caulescens is found along the escarpment. Eight specific habitats are shown, identified with circles. They are the Soutpansberg, then south through Woodbush, Cypress Point, Mariepskop, Gods Window, Pinnacle and Ngodwana into northern Swaziland. There are undoubtedly many more than that, many of them unknown because of the mountainous terrain, separated perhaps by anything from 1 to 50 km from each other.

Acocks, who spent his career mapping the vegetation of South Africa, stated that in the middle of the last millennium the sub-tropical forest stretched thickly along the escarpment, and since then that it has receded into sometimes isolated areas, mainly on eastern and southern aspects, as the world climate has changed. Clivia populations, dependent on forest canopy, will have shown similar reduction, and their isolation from each other has resulted in the development of different forms within species. For example, the caulescent (stemmed) form is due to the elongation of the stem between the leaf scars (up to 20 mm), which appears to be most prominent at Gods Window. If all Clivia produce say five leaves each year they will have the same number of leaf scars, and stem length will not be an indicator of species age. In the other species the leaf scars are very close together, but short bare stem specimens have been seen in all of them.

Most Clivia in habitat are found on slopes in light well-drained soil. Their drought resistance comes from the thick layer of velamen surrounding their roots (as in orchids), and the velamen absorbs and stores water well. This resistance to dryness gives Clivia the ability to be opportunistic soil-less epiphytes (on trees) or lithophytes (on rocks). However, in these cases they are normally found on flat surfaces or in nooks and crannies where there is substantial detritus from the forest cover, in the company of other epiphytes such as moss. Only one specimen (a gardenii) has been seen virtually bare root on the side of a tree. This supposition is backed by the fact that there is no way that Clivia seed can be wind dispersed as in orchids, but they must have been dropped in the trees/rocks by birds, apes, rodents, etc, all of which have been seen taking berries. Once the first plant has established itself high up on the tree or rock, its seed will then fall down in due course so that the number of plants in the community increases.

Come and see for yourselves.