E. J. BUTLER. if 
that of a leaf, and it must be considered as merely a modification 
of the commoner form of median prolification, in which the 
bud consisted, instead of a leafy shoot, of a leaf united at the mar- 
gins to form a tube, within which, at the base, the rudiments of a 
second leaf were often formed. Hairs and stomata occurred on 
both surfaces, within and outside the tube wall. In some cases 
the union of the margins was imperfect, only occurring at the base, 
while the top was an inrolled blade. 
It must not be supposed that all these changes occur in each 
diseased ear. As a matter of fact, there is the greatest possible 
variation between one diseased ear and another. In some, the 
bristles alone are affected, in others, the glumes show the most 
marked alterations, while in others median prolification is almost 
universal in the florets. 
Besides the ears, the leaves of plants affected with this disease 
show more or less considerable changes. In young plants, or in 
early stages, many leaves may be seen with the usual fresh green 
colour changed wholly, or in part to whitish, and later to brown. 
The whitening of young leaves is visible usually as long streaks, 
often occupying half or more of the leaf surface, in transverse dia- 
meter, and extending almost the whole length of the leaf. In older 
plants the leaves affected are chiefly those from whose axils the ear 
stalks spring. These are more completely whitened than in younger 
plants, and the colour rapidly changes to yellowish brown. At 
the same time the leaf is deformed, being twisted and transversely 
folded, and shows a great tendency to shredding of the blade to- 
wards the tip (plate IV, fig. 1). This shredding is also shown in 
plate IV, figs. 2, 3, in other plants affected with the same disease, 
but is not usually so evident in Pennisetum, as in these. In old 
plants, when the green ears are fully developed, the upper leaves 
are mostly browned, and many of them similarly split. Many 
leaf buds in branching stalks are contorted, a mass of small white 
or brown twisted leaves being enclosed within the contorted outer 
leaf sheath (plate IV, fig. 1). 
A considerable number of cases of virescence, prolification, 
and other modifications of the flowers of plants is known to be the 
