154 THE JOURNAL OF INDIAN BOTANY. 



of which trees of nearly 300 ft. with a bole 150 ft. before the first branch 



are common. Their slender trunks 30 ft. round, are covered with a white 



mottled bark, so that the;/ " suggest the columns of some mighty cathedral." 



Except in the region of these Karri the forest is open and park like, with no 



thick or tall undergrowth— a Savannah woodland. 



P. P. F. 



Fungi. 



Sundaraman, S., Usfcilago Crameri Koem on Setaria ifcalica Beauv. 

 Bull. No. 97 of the Agr. Res. Inst. Pusa. *As. 4. 



It has long been known that smuts of various kinds cause great loss in 

 cereal crops and this is an account of the investigation into that of Setaria 

 italica which is grown very largely in South India and more especially in the 

 North Central districts of Cuddapah, Kurnool, Bellary, Anantapur and 

 Guntur. 



Mr. Sundaraman finds that the smut spores germinate freely in distilled 

 water even up to 95 per cent, in 12 hours, but failed to germinate when 

 placed in solutions of copper sulphate of 0. 5% for 15 to 30 minutes. The 

 fungus enters the plant in the young seedling stage but does not infect the 

 flowers and the grain is the only part in which it shows itself. Though some- 

 times the upper spikelets may not show smut while those lower down do, 

 in no case is the reverse found. This of course is because the fungus has en- 

 tered the plant at the base and crept upwards. It will be seen that in no 

 important detail is Ustilago Crameri different from species common in 

 Europe. But the results are useful as confirmation of the life history of 

 smuts and this kind of work is very necessary. 



P. F. F. 



Physiology. 



Coville, Fredrick V. The Influence of Cold in stimulating the 

 Growth of Plants. Jour. Ag. Res. 20 : 151-160. 1920. 



For trees and shurbs of cold climates to become dormant low temper- 

 atures are unnecessary. But for the resumption of growth after dormancy 

 chilling is required. The stimulating effect of cold is limited to the part of 

 the plant exposed to cold. This effect is produced by the digestion of starch 

 to sugar, due to the weakening of the cell-membrances which separate the 

 enzyme from the stored starch. The accumulation of sugar hastens growth 

 by virtue of the higher osmotic pressure imparted to the cell. 



The author discovered, first in his work with blueberries and confirmed 

 by observations on many other plants of the temperate regions, that shoots 

 kept during the winter in a warm greenhouse fail to develop their dormant 

 buds in the spring. A single freezing does not suffice to make the buds de- 

 velop, but a period of two or three months of exposure to cold is required. 

 This characteristic is a safety device which prevents the premature leafing 

 and flowering of plants during warm periods in early winter and their sub- 

 sequent death. The necessity of chilling explains why such fruits as apples 

 and pears do not grow successfully in tropical regions. What the gardener 

 speaks of as " resting " is often merely the period of chilling. 



