50 
THE FERNS OF SOUTH AFRICA 
does not appear unless its requirements are met. But some 
ferns (such as the Bracken) are cosmopolitan if their re- 
quirements are met, and it is surprising how many South 
African species are not endemic and not even confined to 
Africa, but represented frequently in one or more of the 
other continents or ocean islands. In this connection it is 
interesting to read in the late Sir George King’s Sketch of 
the Flora of Rajputana (1878), a carroid 1 province in north- 
west India corresponding somewhat with the frostless portions 
of South African thorn-veld , that the richest part in crypto- 
gamic vegetation is the isolated mountain mass Aboo, “but 
even there only about a dozen species of ferns occur, and of 
this small number only Adiantum caudatum , Adiantum lunu- 
latmn , Cheilanthes farinosa, N ephrodium molle, N ephrodium 
cicutarium , and Actiniopteris radiata can be said to be 
abundant. Adiantum capillus-veneris is found in a few 
spots, and Botrychium virginianum is very rare In the 
eastern tract, the only ferns ever seen are Adiantum lunu- 
latum and caudatum , N ephrodium molle , and Actiniopteris 
radiata . These species occur very sparingly indeed in the 
western tract, and only in shady crevices of rocks, or on old 
moist walls. In wells, the maiden-hair, Adiantum capillus- 
veneris , is occasionally met with on both sides of the 
Arvalis.” 
Strangely, every species mentioned except Botrychium 
occurs also in Rhodesia, though it must be admitted each 
has a fairly wide distribution. 
But if these and other species can cross continents and 
oceans, and germinate wherever they find conditions suit- 
able, then it is not surprising that the distribution of ferns 
in this sub-continent is regulated mostly by the physical 
features. 
Speaking generally, ferns enjoy a humid atmosphere and 
a certain amount of shade. There are of course exceptions, 
but apart from these the somewhat delicate texture of the 
fronds indicates that association. Such conditions also favour 
the growth of trees, consequently trees and ferns are often 
1 For “carroid” see General Index and Glossary. 
