Green Leaves at Work 97 
minute chlorophyll-bearing seaweeds, which live 
near the surface of all but the very coldest wa- 
ters, and are the floating pastures of the sea. 
In plants which habitually bear richly-colored 
leaves—in the copper-leaved beech, for instance, 
or the copper-hazel—chlorophyll bodies are present 
and busy, just as they are in those plants which 
bear green foliage; but the leaf-sap contains some 
strong pigment which overpowers and masks the 
green. Some of those minute plants which have 
a great and evil reputation under the name of 
bacteria contain a purple coloring-matter which 
seems able to fulfil the office of chlorophyll. 
By aid of this pigment they can form organic 
matter when they are exposed to the light. 
A few other bacteria can form organic matter 
in the dark, and unaided by any pigment, green 
or purple. 
But such ‘‘exceptions being excepted,” the 
vividness of the green in stem or leaf is in direct 
proportion to the plant’s self-helpful activity, for 
in the vegetable world the very young and the 
very shiftless are of green. 
But when a plant begins to form habits of 
parasitism the leaves grow dim, and the more 
confirmed these bad habits become, the less chlo- 
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