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1883.] Mosses. 609 
should always consult some specialist, otherwise he is likely to 
commit an egregious error in his investment. 
` Mosses can be studied throughout the year, hence they afford 
a most delightful winter occupation. Certain species, varying with 
the season, can always be found in condition, but of course 
some regions are much more favored than others. In the White 
mountains, for instance, mosses literally cushion the rocks, clothe 
the standing or fallen trees, and spread over the ground. Often 
they hang from moist cliffs in those billowy curves assumed by 
Snow heaps on a roof. The traveler sinks knee deep in the drifts 
they form. The number of species is often bewildering. A mat 
removed, say from some wind-fall, is discovered to be a tangle of 
many kinds. It would require an expert to separate them. Often 
they are found, as in the case of the genus Fontinalis, trailing in 
springs or running streams. They climb, too, high up into the 
Alpine regions, some kinds being found only on giddy mountain 
ops. 
A few words about the study of these bewitching little plants. 
One first has to determine whether the fruit is ¢erminal or lateral, 
that is, whether borne at the ends of the stems or as an outgrowth 
from the sides. Mosses are by this means divided into two great 
Sections, the Acrocarpi and the Pleurocarpi. Any Polytrichum 
would be an example of the first class, and a Hypnum of the 
second. It is not always an easy matter to determine this point. 
Having settled it, however, one next examines the urn, capsule or 
theca (it is known by either of these names), to discover whether 
or not it is covered by an operculum. This is a sort of lid, which 
May be deciduous or persistent. If it does not fall away the plant 
is looked for in Section A of the artificial key of Gray’s Manual 
(edition of 1863, now out of print and rare). Otherwise we pro- 
ceed to Section B. Under this second head we find that the mouth 
the peristome. Delicate manipulation may be required to esti- 
mate them, both in the use of the lenses and illumination, and in 
the handling of the knives and needles. External to the teeth 
