THE CONDITIONS FOR THE: DISTRIBUTION OF PLANTS, 101 
temperature according tolocality, and that this variation is chiefly due 
to adaptations for excesses of temperature or to more or less 
developed means of protection against climatie influences. Here we 
never experience any severe cold, and I need not dwell upon the 
means by which plants are protected against the injurious effects 
of a low temperature, but shall only mention that these are often 
j similar to those intended for protection against heat; in many 
cases, however, the medium of protection is the snow, which 
fact explains the tenderness of many Alpine plants, when cultivated 
in temperate regions. The heat of our climate is at times very 
trying, not only for man but also for plants, and most of orr plants 
are therefore provided with means of protection against the heat 
and aridity of the long dry season. The Indian tropical flora is in 
comparison to that of more temperate climates singularly rich in 
arboreous species, a fact that may be accounted for by the greater 
resistance of a woody structure to excesses of heat. I cannot here 
deal with the structure of the wood and the stem of a plant, bat 
must restrict my remarks to point ont that it is especially adapted to 
protect the plantsagainst climatic exigencies, and that in this respect 
perhaps the cork, the liber or bast, and the bark are very important 
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parts of the wood. It is therefore not surprising to find that both 
cork and liber are frequently very conspicuous in Indian trees. I have 
bt (fact only seen very few where the cork is not clearly visible, if 
not otherwise, then by lenticels on the young shoots, especially 
When these are glabrous. It is alsoa well known fact that many 
Indian trees are rich in fibre, which is generally the produce of a 
well developed liber. 
r . ’ . oa 
The next object for observation is the pubescence or harriness of 
plants, which though apparently insignificant, is of the utmost 
importance for protecting plants. As far as I have been able to 
judge from observation of plants that have as yet come under my 
notice, I think it is a fact that most herbaceous plants, when 
completing their growth during the rains, are more or less glabrous ; 
while those species, which continue their growth during the dry 
Season, are generally more or less hairy. You will notice this by 
observing the weeds of this season. Asan example, I shall mention a 
few of the numerous species of the genus Blumea, which is singularly 
interesting also in other respects. The most common species, 
Blumea membranacea muralis, which grows on old walls and on the 
inside of wells, has almost completed its growth when the dry 
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