166 THE AUSTRALIAN NATURALIST. 
The sporophyte (Fig. 8c) consists of (a). the stalk or seta, 
(b) the capsule, whose structure can be seen by cutting a cross- 
section (Fig. 9). Working from the outside is ( a) the wall 
of several layers of cells: (b) next is an air chamber with nu- 
merous multicellular strands or trabeculae containing chloro- 
plasts; these extend from the wall to the (c) spore-sac, a narrow, 
cylindrical sac, which in the young capsule encircles a solid cen- 
tral axis, called (d) the columella. In older capsules the colum- 
ella is practically hollow, for the spore-sac and outer layers of 
the columella grow more rapidly than the central part of the 
latter, and it becomes torn into strands (trabeculae) similar to 
those in the outer air chamber. 
If we examine the young capsule, a curious hood-like struc- 
ture is seen to cover the whole sporophyte: it is called the 
Calyptra (Figs. 8 and 10), which is the remains of the wall of 
the archegonium. Numerous long, yellowish-brown hairs cover 
the rather small bonnet-like Calyptra-proper, and these clothe 
the capsule. 
As the seta elongates the Calyptra is torn away and carried up 
with the capsule: the seta curves over so that the capsule is 
placed in a horizontal position, and it is now concave above and 
convex below. 
When mature, the Calyptra falls off, exposing the little oper- 
culum or lid of the capsule (Fig. 11): it is shaped like a dunce’s 
cap. Later the operculum falls, and then a brush of fine white 
bristles is seen projecting from the edge of the mouth of the 
capsule. This brush is called the peristome (Fig. 12), and its , 
function is to’ aid in dispersing the spores, for the bristles are 
hygroscopic. ‘These bristles are not hairs, but represent rows of 
thick cells, between which the weaker bands have become torn 
away. At this stage the water and food supplies are cut off 
from the sporophyte, and the capsule dries, and consists practi- 
cally of wall, spore-sac and peristome. 
The spores may be removed partly by the aid of water, for 
the groove in the upper concave surface would make a little 
gutter for rainwater to run down and carry away some of the 
spores. 
An interesting point is that the male “flower” is probably not. 
truly terminal, for the axis is continued upwards through the 
rosette in a series of tiers, showing 3 or 4 generations on one 
stem. 
