RUBBER (HEVEA) DISEASES 75 
The bark on this tree, though smooth, was thin, about one-fourth 
inch, and the flow of latex was poor. , 
ABNORMAL STEMS AND ROOTS OF SEEDLINGS 
In dense stands of reproduction it not infrequently happens that 
seedlings assume abnormal shapes. This may take the form of a 
fasciation or broadening of the stem, resulting in curled hornlike 
extensions with apical abortive leaf development, or a rosette ar- 
rangement of the leaves may develop. Out of several hundred seed- 
lings examined four such monstrosities were discovered. 
Seeds of Hevea as they are scattered over the forest floor come to 
rest and germinate in various positions. When not very deeply sub- 
merged or scarcely at all, as is usually the case, and with the mi- 
cropyle often pointing upward, the radicle may develop for some 
distance before it enters the soil. This may result in an abortive or 
twisted radicle, with excessive lateral root development. The shoots 
developing from seeds lying in different positions, being retarded by 
the slow development of the radicle, curve about and sometimes form 
complete loops before becoming vertical. The stems of a large 
percentage of the seedlings examined had taken a sharp right-angle 
turn (PL VII, C). This was due apparently in some cases to tho 
development of the shoot beneath the seed and its subsequent upward 
turn, or it may have resulted from the horizontal growth of the 
radicle before entering the soil. 
Seedlings which had apparently suffered some injury to the origi- 
nal shoot, with the development of two lateral stems, were of common 
occurrence (PL VII, C). Straight stems in line with the radicle 
were common only in the cases where the seeds had become thor- 
oughly embedded and in a horizontal position. This would be the 
method of planting in nursery practice. 
ABNORMAL LENTICELS 
On internodes of twigs 1 or 2 years old which had been repeatedly 
defoliated by Dot hid ell a ulei, it was frequently observed that the 
lenticels had developed unusually large intercellular spaces. The 
spaces were filled with a powdery mass of cork cells and often in 
such abundance as to cause longitudinal splits in the epidermis. 
This condition was not observed on normal or uninfected trees and 
is apparently a reaction from the continued loss of the foliar sur- 
face and hastens the drying up of the twig and attack by secondary 
fungi. Latex was found to exude in some cases from these lenticels. 
VARIATIONS IN BARK THICKNESS 
The bark of trees with uniform or symmetrical development of 
crown and brace roots as a rule was of a uniform thickness. In- 
dividuals with strong lateral branches of roots usually developed 
a thicker and more laticiferous bark on the side more abundantly 
supplied with food. 
CORK NODULES ON GREEN STEMS 
Up to a certain age the outer bark of Hevea is chlorophyllaceous. 
Two small trees were observed to have begun the development of 
