


36 FLOWERING PLANTS 
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II. Observations on the Adaptation of Plants to Habitat. 
The vegetative organs of a plant—root, stem, leaf—are the 
~ most affected. 
(a) The plants peculiar to the district should be compared 
with each other. Thus, if plants by the seashore are being 
observed, those known to grow elsewhere should be placed on 
one side, and those growing by the sea alone examined. 
- (i.) Length of roots, or underground stems, should be noted. 
(i1.) Character of stem, whether creeping, stunted, prickly. 
(iii.) Character of leaf. This is usually the organ most 
affected. The external characteristics of the leaf, whether 
thick and fleshy, or. thin, prickly, smooth, or hairy ; the 
colour of the leaf ; the difference between the upper and under 
side; the angle at which light falls on the leaf, and the 
arrangement of leaves on the stem in connection with the 
amount of light each leaf in consequence obtains should all 
first be noted. Then microscopical examination of the leaf 
should be made, in order to ascertain the position of the 
stomata—whether on one surface, if so, on which, or on both 
surfaces. ‘The manner of folding or inrolling of the leaf in 
connection with the presence of the stomata is also important. 
(D) In order to ascertain how far the characters noted are 
due to environment, the growth of the same species under 
different surroundings should be compared. For example, 
_ Rest Harrow, when growing inland or by the sea, in a valley 
or ona hill. Drawings should be made, or the plant dried in 
sand—(this is better than pressing)—for future comparison. 
III. The Influence of Man. 
(a) The effect of thinning trees in a wood on its under- 
growth. ‘This is very noticeable. Lists should be made 
before thinning, and for two or three years afterwards. 
()) ‘The etfect of draining on swampy ground. This in 
time leads to the disappearance of plants. 
(c) The effect of cultivating ground that has formerly been 
uncultivated. The weeds that appear in the cultivated ground 
should be noticed. 
