16 
for each of the varying degrees of shade. At 20 months the shaded 
plants were put in two groups, the 6 plants which had been more 
lightly shaded being put under the unbleached cotton and the 6 
which had been more heavily shaded under the thin black cotton. 
The black cotton, though faded by sun and rain and so affording 
varying degrees of shade, always furnished a denser shade than the 
unbleached cloth. 
The growth made by the 18 vines in the first year averaged about 
22^ feet per vine. The most heavily shaded vines made the quickest 
start, but their growth was much more spindling than that of the 
others, with frailer stems having long internodes and leaves of a 
darker green standing in a more nearly horizontal plane; just such 
growth, in fact, as may be seen on vanilla under a heavy natural 
shade. At a year and a half their growth averaged less than 40 feet 
per vine, while that of the other plants averaged 48 feet. At two 
years the plants in full sun had made very vigorous growth, though 
they were rather yellow and had suffered severely from burning on 
the eastern side, some stems burning in two where they bent over 
the support, but on the western side, which had received less sun, 
they continued to look very healthy and vigorous. The plants under 
the light shade looked best and had the largest mass of vine, while 
the development of those under the heavy shade was greatly retarded. 
The growth of the vines indicated that while vanilla will stand 
plenty of light and will grow vigorously when entirely unshaded (PI. 
II, iig. 2), full exposure to the sun burns the vines badly and is less 
favorable to their development and well-being than a light shade. 
The shade may easily become too dense, however, for the best de- 
velopment of the vanilla if pruning is neglected. 
In another planting furnishing very light and very dense natural 
shade the heavily shaded vines showed much more spindling growth 
than the very lightly shaded ones. 
CARE OF PLANTATION. 
Both shade trees and vines need fairly frequent attention. If the 
soil is good, such supporting trees as Enjthrina corallodendron, neces- 
sarily closely set to furnish sufficient supports for the vines, will form 
a shade much too dense for the best development of the vanilla unless 
given frequent prunings. In pruning the shade, if alternate trees 
rather than all trees are pruned each time, the danger of injury to 
the vanilla vines through a sudden change from shade to sunlight is 
greatly lessened. A sudden exposure to strong sunlight will burn 
many leaves and cause them to rot and will also burn the stems of 
the vines. 
In pruning the shade trees, forks through which the vines may be 
hung should be left within easy reach of the hand, and such limbs 
as do not branch at this height should be cut back to force out new 
