Mosses and Peat 
and may produce nearly an inch of soil. The younger 
fronds not only overlie and overshade the older branches, 
but there is a strong suspicion that they hasten their 
decay by feeding upon them! One sees plumes of 
rhizoids (i.e. root-fibres) fixed upon the withering older 
fronds of the same plant and apparently extracting from 
them any valuable material that yet exists.’ 
Fungus parasites sometimes occur on moss rhizoids, 
but it is uncertain if they possess a well-marked fungus 
assistant or mycorhiza such as one finds with higher 
plants. The liverworts (allied to the mosses) do some- 
times possess one.”* But the moss family has carried 
this power of absorbing water to such a degree of per- 
fection that it often becomes a nuisance to mankind. 
One sees this in the “fog” of ordinary pasture land, 
which is a smothering moss development -which in- 
terferes with the growth of grasses and other plants. 
Such fog appears when the land is so wet or has been 
so much grazed that the flowering plants are not grow- 
ing rapidly enough to keep the moss in check. (One 
can almost always find a few mossy strands anywhere 
even in good pasture and particularly in autumn.) But 
the peat mosses of lowland swamps and of the moors of 
Britain and Ireland are even more serious evils, for they 
occupy, almost uselessly, a large extent of country. 
Such feathery mosses as the Hypnums and Hylo- 
comijums are apt to weave themselves about the stem 
bases of marsh plants and mud plants. They absorb 
and hold water strongly, but in such places, if the ground 
is always water-saturated, the peat moss, Sphagnum, 
will soon appear. It is of a pale whitish or yellowish 
green (often, however, pink-tinged at the tips) The 
stems are upright and branch at every fourth leaf, so 
* A fungus, Mollisia Jungermanniz, assists and depends upon Calypogeia. 
Marchantia, Preussia, and Fegatella also have a mycorhiza, 
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