THE NATURAL HOME OF THE FERNS 51 
found together, and some species of ferns enjoy even the 
deepest shade. 
The distribution of forests and forest patches is almost 
confined to the eastern slopes leading from the edge of the 
high central tableland of South Africa to the Indian Ocean. 
The distribution of ferns follows these same lines and every 
forest has its ferns, and some species appear in every 
forest, from Capetown to the Zambesi. But other species, 
either through insufficient or excessive humidity, or ex- 
cessive or insufficient shade, are not so general in their 
distribution, and some are quite local, or endemic to a very 
limited area. 
There is the further factor of temperature, for many of 
ours are temperate ferns, enduring any temperature in which 
frost is absent, or even in some cases where frost does occur. 
But others are tropical ferns, and only occur under tropical 
conditions. 
The forests of South Africa, though present more or less 
along the whole eastern slope and seaboard, are at their best 
on the steep mountain faces having an eastern aspect, and 
follow more or less the range which begins near the coast 
about Knysna, and is further inland further north, including 
the Amatolas, the Zuurberg and the Drakensberg, the latter 
range being on the boundary between the Cape and 
Basutoland, between Natal and Basutoland, the Orange 
Free State and Transvaal, between Portuguese East Africa 
and the Transvaal, and between Portuguese East Africa and 
Rhodesia. 
The range thus indicated, varying in altitude from the 
coast at Knysna to 10,000 feet or more further north, is 
the home of ferns in South Africa as well as the site of 
most of the forests and forest patches, and the distribution 
of ferns within that range depends mostly on the humidity, 
except that in the northern portion tropical conditions exist, 
and consequently outlying stragglers of species belonging 
further north begin to appear. In no part of the forest 
area does frost penetrate into the forest, though in some 
parts hard frosts occur in proximity to or even in the forest 
4—2 
