24 BTTTJ.17.TTN 1380, U. S. DEPARTMENT OF AGRICULTURE 
According to the reports of eastern investigators this disease ex- 
hibits no marked external characters. An exudation of a reddish or 
purplish colored liquid is sometimes present. The affected area 
beneath the bark which at first is yellowish gray later becomes claret 
colored, and it is bounded by a black line. 
Akers records a disease of the bark common to Hevea in the 
Amazon Valley as a decay of the latex cells on untapped surfaces. 
A copious exudation of latex is followed by a decay of the surface 
bark, which affects the bast and finally extends to the wood, rotting 
away the trunk and killing the tree. 
HORSEHAIR FUNGI 
The small hairlike mycelia of certain species of Marasmius (M. 
sarmentosus Berk, and M. equicrinuz Muell. ; PI. III. C) occasionally 
overrun the stems, twigs, and leaves of seedlings in low wet ground. 
The appearance is somewhat like that of long coarse brown horse- 
hair; hence the name. A similar condition is recorded in the East 
and appears to be quite common on rubber, tea, and many jungle 
plants. This mycelium was observed several times on rough bark at 
the base of young rubber trees as well as on seedlings from 2 to 3 
feet high. On low jungle plants among swamps the mycelium was 
sometimes very conspicuous, forming tangles of considerable extent. 
In one case the knives of a seedling were so thoroughly entangled 
with this mycelium that the young leaves developing later were ill 
shaped and deformed. 
In the most pronounced cases observed the appearance of plants 
was as though they had become entangled in a mass of horsehair. 
The strands in most cases had their origin at the base of the plants 
and could be traced outward, over and through the forest litter. 
That the growth on rubber in such cases was purely accidental was 
evident from this fact. When not connected with the ground the 
filaments on leaves or on the bark of mature trees exhibited no com- 
mon point of origin but ramified promiscuously in all directions. 
The filaments are rarely appressed to the substratum throughout 
their entire length, as is the case in the gray thread-blight, but they 
are attacked at intervals by small irregular mycelial pads consisting 
of small hyphae of a lighter color than the cords and may radiate 
outward from the common base. These holdfasts adhere very firmly 
to the epidermis of the leaf or young stem. The cords may break 
before the pads will pull loose. The epidermis on the leaves is 
usually discolored at the point of attachment, but the mycelium 
has not been observed to penetrate the tissues of the leaf. The 
fungus obtains its nourishment from dead substrata. 
The fructifications were rarely found on the aerial cords and then 
only in the dampest situations. At the base of seedlings or on the 
forest litter the fructifications were sometimes abundant. They 
spring directly from the cord, varying in distance from each other 
from a few millimeters to several centimeters. The fructifications 
are of the small mushroom type, w T ith delicate or tough membranous 
semitransparent pi lei set on stalks of the same size and color as the 
cords. The gills are widely spaced and correspond to radiating 
grooves on the upper surface. The color of the pileus varies from 
whitish gray to brown, according to the species. 
