344 MR. M. C. POTTER ON THE 
tection against heat and drought; and I now propose to give an 
account of the special contrivances whereby the safety of the 
young leaves is ensured and how they are protected during their 
early growth from the direct rays of the sun, and thus saved 
from harm or partial destruction. 
For the purposes of description it will be convenient to con- 
sider these special protective contrivances under the following 
four heads, viz.:— 
1. Protection by means of stipules. 
2. "à „ position assumed when young. 
8. = » Shade from older leaves. 
4. » ». gum. 
l. Protection by Means of Stipules. 
ÅRTOCARPUS. ` 
The two species of Artocarpus, namely A. integrifolia, L., and 
A. incisa, L., both of which grew in the Royal Botanic Gardens 
at Peradeniya, Ceylon, supplied abundant material for the inves- 
tigation of the use of the stipules in protecting the young leaves. 
In A. incisa the stipules of a leaf, as is well known, together 
form a hood which completely envelops all those leaves which 
develop subsequently to itself (Pl. XLV. figs. 1 A and B, a) 
upon the same shoot, and thus a stipular hood alternates with 
every leaf. In this plant, therefore, we have an excellent oppor- 
tunity to determine whether the stipules are protective or not; and 
if they are protective, to what degree the leaves enveloped by the 
hood would be injured by its removal and by the consequent 
exposure of the developing leaf to the external atmosphere. For 
this purpose I removed the stipular hood from several young 
shoots at a time when the hood was exposed to the air and still 
covering a young leaf, taking care not to injure the enclosed leaf. 
These young leaves were then allowed to grow, but, consequent 
upon their too early exposure, they never attained their full and 
natural size, but were imperfectly developed and permanently 
deformed. Three of these injured leaves I selected, and at 
the same time photographed with them a perfectly developed 
and natural leaf. These four leaves have been accurately repro- 
duced in fig. 2 (Pl. XLV.), in which A is the perfect leaf, and 
B, C, D the injured ones. A comparison of B, C, D with A 
proves tbe necessity of protection by showing to what an extent 
the leaves were injured by the removal of the stipular hood, and, 
