THE EUROPEAN SPHAGNACE® 118 
the branches must be cut. The razor must of course be kept 
exceedingly sharp, and whilst the sections are being cut the whole 
blade should be kept well moistened with spirit. The sections 
ter 
To correctly make out the pore structure, it is necessary to stain 
the leaves. For this i 
methyl-violet gives the best results, and need only be allowed to 
act inute 
, hsi 
methyl-green, and saffranine, &¢., also give satisfactory results ; 
while, if permanent preparations be desired, hematoxylin should 
be used, and the leaves in that case should be mounted in Canada 
balsam. 
Russow describes four types of pores as follows :—(1) Non-bordered 
perforations with thin and delicate outlines, and which can only 
clearly seen in stained preparations. These BEES esd found in 
r eaves. 
Bordered pores, in which the opening is surrounded by a distinct 
thickened ring, which may be of greater or lesser thickness. This 
is the most usual form of pore found in the bog-mosses. (8) Hof- 
poren, in which, within the thickened ring, is a wider or narrower 
band of the unthickened cell-membrane, so that the actual per- 
foration is relatively very small, and is, as it were, surrounded by a 
courtyard (Hof). Sometimes there are two perforations within the 
same ring. (4) Pseudo-pores. These are round or oval rings of 
thickening, which are very commonly found in some leaves, espe- 
cially in the Subsecundum group, and which in unstained pre- 
parations closely resemble true bordered pores. On staining 1t 
will, however, be found that the cell-membrane within the ring is 
than they really are. ; 
The structure and distribution of the pores frequently differ 
greatly on the two surfaces of the same leaf, and, as will be seen 
in the following clavis, it is often essential to clearly make out these 
oints. This is in almost every case easy, as, owing to the con- 
Following the descriptions of species I have endeavoured to 
indicate the main varieties that Warnstorf recognizes, but have not 
