RUBBER (HEVEA) DISEASES 19 
are borne laterally near their extremities. The perithecia are devel- 
oped on a dense carbonaceous layer at the surface of the soil. The 
wall of the perithelium is slightly roughened, but soon becomes 
smooth, and is shiny after long exposure. 
Another species of Rosellinia found on dead roots in contact with 
those of Hevea and apparently causing disease is R. siibiculata (PL 
XI, B). R. australis is common on dead roots of cacao (PL XI, C) ; 
R. puiggarii (PL XI, E) was found on Hevea roots and a species of 
Schizostoma (PL XI, D) on various dead roots in plantations. 
These species should be carefully studied. 
STEM AND BRANCH DISEASES 
PINK DISEASE 
The pink-disease fungus (Corticium salnfnonicolor Berk, and Br.) 
is widely distributed in the American Tropics, being recorded from 
Porto Rico, Trinidad. Dominica, and St. Lucia. It is common on 
the stems and branches of cacao, and is recorded on grapefruit, 
lime, orange, oleander, pigeon-pea. and amherstia. In the Orient 
the fungus attacks a great variety of hosts. Butler states that it 
has hosts belonging to the most diverse families, a range perhaps 
wider than that of any other tropical parasitic fungus yet known. 
and he records it on 41 different economic hosts. Petch states that 
in Java 141 different species of plants are known to be attacked by it. 
In the East the different hosts are not equally susceptible. Ex- 
periments have shown that the fungus readily passes over from one 
species of host to another, but there is no indication that biological 
races exist. Hevea, Castilloa, and Ficus are especially susceptible 
to the disease. Yincens records a species of Corticium found at 
the base of shoots of Hevea which he suggests might be C. sal- 
monicolor. He states that it appears to be harmless. Later, the 
same author records the fungus on Hevea in the Amazon Valley. 
During the present investigation the fungus was found on dead 
branches of Hevea attached to the living tree; but there was no 
evidence that it was acting as a parasite, since there was no exten- 
sion of the fungus beyond the branch collar. It is possible, how- 
ever, that its activities might have been arrested after the death of 
the branches or by drought. Its appearance on citrus was of a 
niore decisive character and was the cause of considerable damage. 
The fructifications of the fungus on Hevea generally originate 
in the forks of the branches and form pink or rose colored incrusta- 
tions on the bark. These incrustations become whitish or completely 
bleached with age. and the surface cracks into fine lines more or 
less at right angles to each other. Like many species of the group, 
both the mycelium in the wood and the fructification are resistant 
to drying. The structure consequently revives during rainy weather. 
at which time spores are being produced, and it may then again be- 
come pinkish or waxy. 
The fungus may appear in any one of four different stages. The 
typical or Corticium stage here described was the only one ob- 
served on Hevea. On lime and cacao all stages were found. At the 
margins there is frequently an extension of the mycelia iirthe form 
of fine silky hyphae which form a thin silvery white semitransparent 
