BRYALES 281 
No accurate statements are to hand showing the genetic relation of the 
endothecium to this central tract, but it certainly gives rise to the greater 
part, if not exclusively to the whole, of the conducting strand. 
In the upper region assimilating tissue is usually developed in more 
or less close relation to the capsule itself, together with numerous and 
often large intercellular air-spaces. These developments are derived chiefly 
from the amphithecium, while at the same time the sterile cells of the 
columella usually expand, as a tissue for water-storage: 
‘contain some chlorophyll, and occasionally forms air-spaces. 
shape of the capsule is chiefly 
due to these changes, which are 
obviously secondary. Different 
types be — distinguished 
according the assimilatory 
system is developed from the 
of the capsule itself, or 
partly here and partly in the 
apophysis below, or entirely in 
the region of the apophysis. 
For instance, in Bartramia the 
this may also 
The swollen 
may 
as 
wall 
assimilatory system is chiefly in 
the wall of the capsule, where 
it is equally developed all round. 
In Buxbaumia (Fig. 137, 8, 9) the 
same is the case, except that 
the development is dorsiventral : 
: vi 
the capsule early takes an oblique 
position, and the assimilatory vale 
tissue is developed more strongly Splachnum luteum. 1. Capsule open. dA =apophysis. 
II. Unopened capsule in longitudinal section. s=seta; 
on the better-lighted side. In 
other cases, however, the assimi- 
latory system extends some dis- 
Lx«=leptoxylem; sf=stomata on apophysis; c/=colu- 
mella ; #=peristome ; 4s=archesporium ; 7=intercellular 
space. III. and 1V. Diagrams to illustrate the opening 
of the capsule. (From Goebel, after Hedwig, Vaizey, and 
Bryhn.) 
tance below the actual capsule, 
constituting the swollen region of the apophysis: this is of small size in 
Polytrichum, and the assimilatory system is chiefly here also in the wall 
of the capsule, but it extends downwards to the small apophysis, while the 
numerous stomata lie in the narrow neck between these parts. 
Mosses, again, the apophysis itself becomes the chief seat of assimilation, 
as, for instance, in Funaria (Fig. 137, 5), and this leads to its enlargement : 
so much so that it becomes the most prominent feature in the whole 
sporogonium: thus in the Splachnaceae it is commonly larger than the 
capsule which it is to nourish, and in S. /utewm (Fig. 138) it appears as 
a wide umbrella-like expansion, which shows a structure not unlike a 
leaf-lamina, with well-marked epidermis, spongy mesophyll, and stomata 
upon the upper surface. Still, with all these variants at or near to the 
In many 
