Part III.] R. S. Hole: Useful Exotics in Indian Forests . 
17 
(5) Depth of water-table. 
(c) Whether soil well-drained, or liable to water-logging, as is 
for instance the case in low-lying heavy soil which has 
been trampled and compacted by cattle in wet weather. 
( d ) Presence of water due to percolation from streams or canals. 
(i e ) Annual rainfall and its monthly distribution. 
[f) Whether sheltered, or exposed to strong winds. 
{g) Elevation above mean sea-level and aspect. 
( h ) Temperature, especially the maxima and minima tempera¬ 
tures at different seasons and liability to frost. 
(i) Humidity of the air. 
(j ) Liability to sno.wfall and at what season. Australian 
species of Acacia and Eucalyptus planted in the 
Himalayas have frequently proved unable to withstand 
the snowfall. 
(k) The general type of the existing vegetation, i.e. } whether 
xerophilous, mesophilous, or hygrophilous, and its 
periodicity. 1 
(VI) Having ascertained, so far as possible, the conditions of our 
localities as detailed above, it is advisable to collect inform¬ 
ation under heads ( a ) to ( ic ) regarding the conditions 
which characterise the natural habitats of those exotics 
which, from their economic reputation, appear to be desir¬ 
able. Attention must also be paid to the following 
points - 
(a) The characters, xerophilous or otherwise, of the plants, many 
of which can be recognised in an ordinary herbarium 
specimen. These will to some extent compensate for 
lack of precise information regarding the habitat ; (b) 
the periodicity of the plants and natural time for germi¬ 
nation of seeds. The natural period of vegetative 
activity is of great importance, for plants which can, for 
instance, withstand extremes of temperature when leafless, 
may be killed by comparatively moderate temperatures 
when in leaf; (c) whether in nature they usually grow 
best in the shade of other plants or are able to directly 
For an explanation as to wliat is here meant by such expressions as “ xerophilous type 
of vegetation” see Indian Forest Memoirs t Botany, Vol. I, Part I, Introduction, 
especially pp. 5—11 and 22—28. 
[ 141 ] 
Information 
required 
regarding the 
exotics. 
