DESCRIPTION OF PLATES. 177 
So in higher plants, the peculiar structures un- 
der consideration (plant hairs) owe their form 
to a moulding power residing in the living pro- 
toplasm contained in their cellular envelope, 
which is derived from the little mass of proto- 
plasm detached from the parent— the fertilized 
ovule —in which the potentiality which has re- 
sulted in this wonderful development was at 
one time stored up. But this hereditary trans- 
mission of ancestral features does not result in tame 
uniformity. While in a general way plants and 
animals resemble their parents, there is sufficient 
variation in detail to make every individual dif- 
ferent in some respect from others of the same 
species. Thus, among plant hairs we may find 
upon the surface of the same leaf various modi- 
fications of the characteristic form. Upon the 
leaf of Lavatera ascergentifola, for example, the 
stellate hairs sometimes have but two or three 
rays, while others in the same field of view may 
have as many as seven or eight. 
The phenomenon of cyclosis, or rotation of the 
protoplasm within the cell, may be favorably 
studied in the hairs of certain plants, e. g., in 
Tradescantia. 
It will be seen from what has been said, that 
plant hairs are interesting objects of study, not 
only for the amateur microscopist who seeks 
curious and beautiful objects for his cabinet, but 
also for the biologist and the student of vege- 
table physiology. 
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