684 TRANSACTIONS OF SECTION K. 
seen easily ; they are more commonly in considerable aérial gardens than solitary, 
for the presence of one plant enables another to get a footing. As with the 
forest trees, the larger-leaved epiphytes are rarely in the topmost layers of the 
forest, but live a little below. 
Mosses and film-ferns are abundant on the tree-trunks; neither store water, 
but both withstand desiccation. Two film-ferns were sent alive to Kew in a 
letter—a matter of a month in post-bags—without any protection against desicca- 
tion, and are now growing there. 
Epiphytic figs are common in the forest, where the crown of one attains a 
greater span than other trees, and its roots find their way to the soil more than 
one hundred feet below. 
The forest attains a height of 120 to 180 feet. Phanerogamic parasites are 
common in it, showy mistletoes living in the tree-tops, and leafless parasites being 
common on the ground, such as the coral-red Balanophora dioica and brown 
Lhopalocnemis phalloides (Balanophoracee) and dark blood-red Sapria bengalensis 
(Cytinacee), which live on the giant vines, where these, running through the 
tree-tops, make the light on the ground below too dim for foliage plants. 
The lecturer measured the light in several places, finding it reduced to ;1; to 
gua and even to 1, of full sunlight. 
As far as known to the author, from the observations of Major Sweet and 
Lieutenant Oakes, coniferous forest commences at 9,000 feet in the hills beyond 
those which he was able to visit. : 
TUESDAY, SEPTEMBER 10. 
Joint Discussion with Section D on the Origin of Life.-—See p, 510. 
The following Papers were then read :— 
1. Vitality and Distribution of Growth in Defoliated Larch Trees.~ 
By Auan G. Harper, B.A. 
Trees partially or completely defoliated, in two or more successive seasons 
by the larve of the large larch saw-fly (Nematus erichsonit). 
General effects of the defoliation : (a) reduction in radial growth increment; 
(b) reduction in the ratio of autumn tracheides to the total breadth of the annual 
ring. 
In extreme cases the radial growth increment ceases entirely, or the cambium 
is active over parts only of the circumference, so that a partial ring results. The 
autumn tracheides may have their walls no more thickened than those of the 
spring wood, but are smaller in size. Or the earliest formed tracheides may be 
normal, but those formed at the close of the growing period are again thin-walled, 
the food supply having run short. 
Both these effects, reduced growth and reduced percentage of autumn wood, 
are greatest at the base of the trunk and steadily decrease as one proceeds upwards, 
Three examples :— 
A. Forester’s report on tree at time of felling, Flourishing.—A radial growth 
increment has been found every year since before the beginning of the attack, 
both at base and at the top and in all parts of the trunk. For one year the 
autumn tracheides remained totally unthickened, but there has been a recovery 
during the last two years, both in size of the increment and in percentage of 
autumn wood, and this recovery is much more marked in the upper part of the 
tree. 
C. Forester’s report, Dying.—As in B, growth at the base had ceased two 
felling, but the upper parts still continued to grow in thickness, and at the tip of 
the tree there was a slight recovery of the autumn wood percentage in the last 
year before felling. 
C. Forester’s report, Dying.—As in B, growth at the base had ceased two 
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