In following Professor Schimper in the separation o f the
Sphagnmm as a sub-class from the Bryince or true frondose
mosses, I can simply record my conviction that this is b y far the
most satisfactory mode o f dealing with them, since the y possess
in their structure various peculiarities, which are not shared in
b y other mosses. It is to be regretted that this great bryologist
has changed his views on this point, for in the second edition of
his Synopsis he brings together the Archidiacece, Andreaacea,
and Sphagnacea, as Bryince anomalce, without supplying any
character for the same, though it is clear that the only common
bond o f union is the large saccate calyptra, tearing open irregularly,
and they thus correspond to Hampe’s section Saccomitria.
T h e sub-class Sphagnince may be defined as follows
“ Plants densely aggregated, without roots except in the young
state. Stem with the axile cells soft, becoming indurated at the
surface, clothed with a cuticle o f one or several layers of large
la x cells. Lea ve s nerveless, o f a single stratum o f dimorphous
cells, the small utricular ones conveying sap and chlorophyl,
enclosing the large, empty hyaline ones, which generally contain
spiral fibres and have their walls perforated by large or small
foramina. Inflorescence axillar, the male amentiform, antheridia
globose, with v e ry fine, branched paraphyses. Capsule globose,
sessile on the apex of an elongated vaginula ; calyptra saccate.
Branches in lateral fascicles, aggregated at summit into a dense
coma.” T h is will comprise only a single family and a single
genus— Sphagnum.
In no genus o f frondose mosses do the branches occur in
lateral fascicles springing from one p o in t ; nor do we find in any
the peculiar dimorphous areolation of the le a v e s ; the nearest to
them in this respect as well as in external appearance is the
family o f Leucobryacece, but in their true structure they are totally
different, and they equally stand apart b y their antheridia and
extraordinary paraphyses, and the loose cuticle investing their
trunks.
A s to the economic uses o f the Sphagnacece, they are but small,
except as a source o f easily procured fu e l ; and in this respect
indeed they are o f immense importance, for no substitute could
be found in the thinly populated and barren districts o f the north,
where trees become an insignificant object in the scenery, or cease
to grow at a l l ; y e t nature, by the v e ry means which produce
these widely extended solitudes, supplies one o f the first requirements
o f those who occupy them, and everywhere is peat annually
cut, dried, and stored.
With regard to the function o f these plants in the formation
o f peat, I cannot do better than quote Professor Schimper’s
words. H e says :— “ Unless there were peat-mosses, many a bare
mountain ridge, many a high valley o f the temperate zone, and
large tracts o f the northern plains, would present an uniform
watery flat, instead o f a covering o f flowering plants or shady
woods. F o r ju s t as the Sphagna suck up the atmospheric moisture
and convey it to the earth, do they also contribute to it by
pumping up to the surface o f the tufts formed by them, the
standing water which was their cradle, diminish it b y promoting
evaporation, and finally also b y their own detritus, and b y that
of the numerous other bog-plants to which they serve as a support,
remove it entirely, and thus bring about their own destruction.
Then, as soon as the plant-detritus formed in this manner has
elevated itself above the surface water, it is familiar to us b y the
name o f peat, becomes material for fuel, and all Sphagnum vege tation
ceases.”
The ir power o f retaining moisture renders them useful to the
gardener in the cultivation o f orchids, ferns, and other delicate
plants, and for their package and transport in a fresh state.
But to the inquiring mind the study o f the structure o f these
plants must prove an unfailing source o f instruction, for in no
members o f the vegetable kingdom do we find means so well
adapted to the ends they serve, as in the beautiful and varied
tissues which build up a single stem o f Sphagnum.