70 
mass.” It was partly on account of this character of the soil that 
Mr. Talbot was led to regard the specialised branches as 
‘pneumatophores. 
The galls of Ischaemum pilosum are described by Mr. Talbot 
as “peculiar, red-coloured axile organs,* clothed with sheathing 
white scales at the base, and somewhat resembling slender goose- 
quills in shape and thickness .. . ey are conspicuous objects 
uring June, July and August, when the rainfall in the Deccan is 
heaviest, on the black soil about Poona.” : 
The mature gall may be described as a cylindrical tube, pointed 
at the apex, and sheathed at the base by scale-leaves (Fig. 1). Its 
length, in the specimens sent to Kew, varied from 11 to 18 cm., and 
its diameter from 3 to 4mm. The pointed tip of the gall consists 
of an indurated, rolled leaf-rudiment, 1-2 mm. in length,t beneath 
which is a short solid portion of stem, or diaphragm. The hollow 
portion extends from this diaphragm to the insertion of the highest 
scale-leaf, i.c., for practically the whole length of the gall, and thus 
represents a single greatly elongated internode. A longitudinal 
section of the gall is shown in Fig. 
The origin of the gall appears to be as follows : The larva of the 
gall-insect finds its way into the meristematic tissue of the stem 
immediately below the youngest leaf-rudiment of the bud,{ with the 
final result that the youngest leaf remains rudimentary, that no 
further apical growth takes place, and that the highest internode 
becomes hollow, and also abnormally elongated owing to long- 
continued. intercalary growth at its base. Comparison with a 
normal branch shows that the internodes of the stem, at a level cor- 
responding to that of the gall, are solid, only 4-5 mm. in length, and 
have the vascular bundles scattered over the greater part of the 
transverse section (Fig. 11), while in the gall-internode the bundles 
show an approximation to arrangement in a single circle (Fig. 10 an 
Fig. 12, which is a portion of a transverse section of a gall enlarged 
to the same scale as Fig. 11). The vascular bundles in the gall 
* The specimens were sent in spirit, and no matter 
had been extract ROrTSs consequently the colouring 
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