24 CONNECTICUT GEOL. AND NAT, HIST. SURVEY. [Bull. 
rows of green cells, which play a part in holding the central 
portion of the. capsule in place. * Of course the stomata afford 
a communication between the air space and the outside air. 
As the spores mature, the photosynthetic tissue breaks 
down, the columella shrivels, and the spores eventually lie 
loose in an enlarged cavity, bounded by little more than the 
epidermal layer of the capsule wall. In a few of the simpler 
genera the capsule bursts irregularly at maturity. In the 
majority of cases, however, it splits by a circular line in the 
upper part, which cuts off an apical portion, or lid, from the 
capsule proper. Sometimes the region of splitting is marked 
by a row of modified epidermal cells, called an annulus, but 
this is not always developed. The walls of the. annylar cells 
have the power of absorbing water readily and swelling, thus 
forcing the lid to separate. After the lid has fallen away, 
the mouth of the capsule usually appears fringed with a circle 
of pointed teeth called a peristome, and in many genera two 
peristomes are developed, an inner and an outer. The inner 
peristome is always more delicate than the outer, and its 
divisions, when present, are called segments, instead of teeth. 
The segments are sometimes separated from one another by 
one or more delicate hair-like’ structures known as cilia. The 
peristome plays a peculiar part in the scattering of the spores; 
in moist weather the teeth come together and close the mouth 
of the capsule; in dry weather they separate and allow the 
wind to scatter the spores. Although the description just 
given will apply to the majority of cases, the structure of 
the capsule may be much simpler or even more complex than 
indicated. Taking the Bryales as a whole, the sporophyte 
shows the highest type of development to be found in the 
Bryophytes. It does not, however, show unlimited growth, 
the entire capsule maturing at the same time, and in this 
respect it is surpassed by the Anthocerotales. 
The Bryales are divided by Brotherus into more than forty 
families, about half of which are represented in Connecticut. 
These are based on the general habit and structure of the 
gametophyte and on the peculiarities of the capsule, many of 
the most important characters being derived from the 
peristome. The species flourish best in moist and shaded 
