6 
THE FERNS OF SOUTH AFRICA 
instead of the cup, there is only a scale placed under the 
sorus. In some other ferns there is no indusium or involucre 
whatever. 
The sorus is generally placed on a vein, and the part of 
the vein to which the capsules are attached is known as the 
receptacle , which in a few cases projects beyond the substance 
of the frond, and in a few others is sunk into it. The capsule 
or sporangium is a roundish body, sometimes tapering down- 
ward into a stalk (Plate 7, Fig. d), and in all our true ferns 
is surrounded by an elastic jointed ring which in some is 
placed horizontally, and in others vertically, but in all it 
seems to assist in opening the capsules for the exit of the 
spores. The sporangia of the allied Orders differ somewhat 
from those of true ferns, and are described under each Order. 
SPORES are minute dust-like germs, from which young 
ferns of the same kind are produced in the manner explained 
in the next chapter. 
Besides the above there are several other appendages, such 
as scales, hairs, glands, ’and woolly tomentum, which, though 
of less use to the plant, are of considerable value to us as 
a means of identification. The other terms used in the 
descriptions are explained in the glossary at the end of the 
book, and the parts of the allied plants are, in each case, 
explained in the description. 
