EUROPE AND NORTH AMERICA. 17 
these cells Mr. Mitten uses the term sfatia or spaces. This 
description applies to the leaves of the branches, but in those of 
the stem and perichztium the two kinds of cells are not so distinct, 
as the chlorophyl is wanting and the hyaline cells are often 
extremely narrow, especially those at the margin, where they 
generally form a more or less wide border. 
The stem leaves in all the European Sphagua differ considerably 
from the branch leaves both in form and structure; they are 
distant from each other, with a 2 arrangement, or five leaves in two 
spiral turns, and are generally reflexed against the stem, as if 
pushed back by the descent of the pendent branches. Their form 
is oblong, ovate, or lingulate, and at their basal angles there 
are generally present more or less evident auricles; they are also 
very uniform on the same plant both in size and shape. The 
areolation is laxer than that of the branch leaves, and spiral fibres 
are rarely present in their hyaline cells; the basal cells form one 
or more rows of incrassate vesicular cells, more or less coloured, 
but the greater part of the leaf is colourless from the absence of 
chlorophy] in the narrow cells. 
The branch leaves are small and closely imbricated, and differ 
considerably on the two kinds of branches, and even on different 
parts of the same branch; on the divergent branches they are 
small at base, becoming larger in the middle of the branch, and 
narrower and more distant towards the point ; the three or four at 
the extreme base of the branch are very small and have a peculiar 
shape, being somewhat obliquely triangular in outline, and partly 
resemble the stem leaf in areolation ; in fact, they convey the idea 
of one half of astem leaf which has been split down the middle, and 
possibly may originate by being torn apart by the separation of the 
branches forming the fascicle, at their first stage of development. 
Russow attaches importance to these leaves, and names them 
intermediate leaves, but they are not always alike in the same 
species, nor do they offer much variety in different species, and 
they have always a broad border of narrow cells ; the leaves of the 
pendent branches are all longer and narrower, as are also their 
component cells. 
The relation of the two forms of cells to each other, in the 
anatomy of the ramuline leaves, is a point of great importance, 
since it originates in the fundamental formation of the leaf, and it 
therefore takes part in the diagnosis of species ; to observe this 
c 
