2 94 
Bews . — Plant Succession and 
Species with Restricted Distribution in South Africa. 
It is interesting to inquire how far the converse of the above rule 
(namely, that species with a restricted distribution or narrow range belong to 
late stages of the succession) does hold for South Africa. It is clear, from 
what has already been said, that it does not hold altogether, for pioneer 
species may have a restricted distribution. Nevertheless there are certain 
large classes of rare or relatively rare species (using rare in the sense used by 
Willis, of being restricted to a fairly small area) which, it will be shown, 
belong of necessity to climax or subclimax stages of succession. In 
a paper (now in the press) ( 9 ) dealing with the plant ecology of the Natal 
coast-belt, I have analysed the floristic composition of the vegetation, and 
have pointed out that as the succession advances in the various seres 
(hydrosere, psammosere, xerosere, halosere), the vegetation becomes more 
and more tropical, 84 per cent, of the genera and 36 per cent, of the 1,500 
coast-belt species extend through the tropics, and there are in addition 
a large number of endemic species. AIL these tropical and endemic coast- 
belt species do not spread outside the frost-free localities on the Natal 
coast-belt, and as far as South Africa is concerned they are rather rare. 
Almost all of them appear late in the succession in scrub or forest. The 
marsh plants and even the grassveld species, with one or two exceptions, are 
all the same as occur in the midlands of Natal and other colder parts 
of South Africa. Among the grasses it is particularly interesting to com- 
pare the various species in the coast grassveld, which, with the exception of 
three or four, are the same as over the whole eastern grassveld region, with 
the numerous tropical or endemic species of Panicmn , & c., which are 
abundant round the moist fringe of the coast forest, but do not enter into 
grassveld. The coast scrub and forest have been analysed in considerable 
detail, and over 700 species have been listed and symbols of relative 
frequency given. The great majority of them do not occur elsewhere 
in South Africa. 
There are over 60 species of Acanthaceae alone, and the family is not 
even represented at the Cape. The numerous climbing species of Asclepia- 
daceae are quite distinct from the more widely distributed grassveld and 
western species of the same family. Tropical members of the families 
Anonaceae, Cappariddceae, Bixineae, Urticaceae, Euphorbiaceae, Cucurbita- 
ceae, Convolvulaceae, Amarantaceae, Verbenaceae, Leguminosae, &c., are 
nearly all confined to this subclimax or climax type (scrub and forest) on the 
Natal coast-belt. Whether 4 wides * or endemics, they are all restricted 
in their distribution in South Africa. 
Elsewhere on the eastern side it is also true that a great many species 
with restricted distribution are forest species. Two endemics which are 
often completely dominant in forests (Podocarpus falcata and Xymalos 
