EUROPE AND NORTH AMERICA. 15 
ventricose at base, and gradually contracted upward into a more 
or less distinct, somewhat arched neck, which is perforated by a 
foramen at apex; they are very distinct in Sphagnum tenellum, 
but in some species the neck is scarcely evident; one of these 
retort cells always falls at a leaf insertion, and they never contain 
spiral threads, even when these are present in the ordinary cells 
of the branch cuticle. 
In most species of Sphagnum the branches which constitute 
each fascicle are of two forms; part of them stouter and directed 
outwards from their insertion, become arched at the middle and 
gently curve downward at the extremity, and these may be called 
the divergent branches; the rest are longer and more attenuated, 
with longer and narrower leaves, hang straight down, and are 
often closely appressed to the stem; these we term the fendent 
branches, and the number and direction of each of these in a 
fascicle is pretty constant in each species. 
The branches always stand close to a leaf, at the end of its 
line of insertion on the stem, and at every fourth leaf a branch 
fascicle is found, their arrangement being in five straight rows, with 
the formula 2, i.e. three complete turns of a spiral contain five 
fascicles. 
Some of the uppermost divergent branches become condensed 
and clavate, and form the amentula of male inflorescence. 
It is by means of the pendent branches and cuticle of the stem 
that the wonderful hydraulic property of the Sphagua is main- 
tained, and this is readily seen if we place an uninjured stem in a 
glass of water and allow the top to hang over the margin, for the 
water rises by this channel, and soon begins to drip from the 
drooping end, until, like a syphon, it has drawn off all the contents. 
Not only do the Sphagua thus give off water to the atmosphere, 
but they can on the other hand also absorb moisture from it and 
transmit it downward ; in this way a constant interchange goes on 
between the stagnant pools and the atmosphere, by which means 
no doubt the former are prevented from becoming putrid. 
Tue LEAVES. 
Hofmeister admirably describes the development of the leaves 
of Sphagnum ; they arise from the outer cell layer of the growing 
point, the first leaf cell appearing from the second, third, or fourth 
cell below the terminal one, and this dividing repeatedly by alter- 
