BRYOPHYTES 
109 
later the sporogenous tissue becomes two layers of cells. The outer layer 
of the amphithecium develops a capsule wall of four or more layers, the 
outermost one being the epidermal layer, 
consisting of elongated narrow cells and 
containing stomata similar to those of vas- 
cular plants. The stomata are related to 
the fact that the wall layers beneath the epi- 
dermis are chlorophyll tissue, giving to the 
sporophyte the ability to manufacture food. 
The intermediate zone adds continuously 
new capsule regions below; therefore in a 
longitudinal section of a capsule the whole 
sporogenous series may be seen, from one- 
layered sporogenous tissue below, through 
two-layered sporogenous tissue, mother cells, 
and tetrads, to mature spores above (fig. 
241). The capsule dehisces by splitting into 
two -valves, which separate downwards as 
the spores mature, leaving the spores ex- 
posed upon the columella (fig. 239). 
In many cases some of the sporogenous 
cells do not form spores. These sterile 
groups of cells break up the continuous 
mass of sporogenous cells into more or less 
. FIG. 241. Anthoceros: longi- 
separated groups. This tendency to break tudinal section through ^^ 
up the sporogenous tissue into separate of a sporophyte, showing bulbous 
smaller masses by intervening sterile tissue foot embedded in the gameto- 
.. . . . . , , , phvte; above the foot is the zone 
is an important fact, which will be referred of - actively divid ,- ng cells elongat . 
to later. These sterilized and somewhat ing the sporophyis; the base of 
modified sporogenous cells are called the capsule shows the P^P 1 * 1 
chlorophyll tissue, the sporoge- 
elaters, but they are different from those nous tissue (at first one layer 
found among Marchantiales. This green of cells, then dividing to form 
sporophyte, with its sterile and elongating two lavers )> and the columella; 
. . . section from middle region show- 
axis, and its sporogenous tissue broken up ing spore mother cells with sterile 
into smaller masses, is very suggestive of a cells between; section from upper 
possible relation to the completely inde- re & on showin g tetrads and 
, , . , .ji sterilized sporogenous cells, 
pendent sporophyte of the ptendophytes. 
Conclusions. Among the Anthocerotales there is a remarkable 
association of a primitive type of gametophyte with a highly developed 
