lO 
THE AMERICAN BOTANIST. 
ve]*)ped, and that all the materials of subsistence are contributed 
by the fungus. 
B( th Indian pipe and false beech-drops may be found in this 
vicinity, the former in almost any wood where leaf mold abounds,, 
the latter usually under oak trees in rather dry woods. The white 
scapes and single nodding flowers of the Indian pipe are familiar 
to every one — the brownish, several-flowered scapes of the false 
beech-drops are less frequently seen. 
As noted above, these two genera, Monotropa and Hypopitys, 
represent the extreme of symbiotism in flowering plants. But the 
inference must not be drawn that all plants which have their root 
systems infested with fungi are necessarily decadent. The fact 
is, almost all forest plants, whether trees, shrubs or herbs, receive- 
more or less nourishment from humus, or vegetable mold, and are 
accordingly partial saprophytes. Many of them also receive the 
assistance of fungi, and are accordingly partial symbiots. Four 
large families of plants are now known to derive such assistance 
in the work of absorption. They are the pine, oak, birch and 
heath families. In them the work normally performed by root 
hairs is largely done by fungus hyphae and strands. These not 
only partially envelop the root, but they also force themselves in 
between the cells of the tissue. A root thus infested has been 
called a fungus-root or mykorhiza. 
It is evident that the story of the dependent plants thus far is a 
story of greater or less degradation. Even before the true status 
of parasites was known the decadent tendency was recognized and 
such plants were suposed to be degenerate outgrowths from their 
hosts. A remarkable thing about dependent plants is that they 
lose entirely the external appearance of a vascular plant and even 
the whole structure oi tissues characteristic of vascular plants,, 
and yet retain unchanged the parts concerned in reproduction. A 
single organ, or parts of organs, may indicate the downward tend- 
ency more positively than the rest of the plant. The haustoria by 
which parasites attach themselves to and draw nourishment from 
other plants are degraded roots. In hemiparasites some divisions 
of the root remain normal while others are degraded into haus- 
