iv. THE ANTHOCEROTES 15.3 



apical part of the capsule retains its meristematic character for 

 a much longer period. Corresponding with this, the growth 

 at the base of the capsule is much less marked. The divisions 

 in the archesporium are much more active than in Anthoceros, 

 and the apical part of the capsule retains its meristematic char- 

 acter for a much longer period. Corresponding with this, the 

 growth at the base of the capsule is much less marked. The di- 

 visions in the archesporium are much more active than in An- 

 thoceros, and also less regular. At first divisions occur in the 

 upper portion in all directions, so that above the columella there 

 is a mass of archesporial tissue much thicker than that below, 

 and occupying very much more space than the corresponding 

 tissue in Anthoceros. Longitudinal sections through the basal 

 part of the older sporogonium show an arrangement of tissues 

 similar to those in Anthoceros, but there are differences corre- 

 sponding to those in the young stages. The foot (Fig. 84, A) 

 is much smaller and flatter, and sometimes shows a very regular 

 structure. The central part is composed of a compact mass of 

 rather large cells, between which and the base of the capsule is 

 a narrow zone of meristematic tissue. The superficial cells do 

 not always grow out into the root-like processes found in 

 Anthoceros and Dendroceros, but may remain short and project 

 but slightly. The cells are characterised by abundant granular 

 cytoplasm and conspicuous nuclei, showing that they are prob- 

 ably not only absorbent cells, but also elaborate the food mate- 

 rials taken in from the gametophyte. The gradual transition 

 of the differentiated tissues above into the meristem at the base, 

 is precisely as in Anthoceros, and sections at that point in the 

 two genera can scarcely be distinguished from one another. 

 The columella (in longitudinal section) in both shows four par- 

 allel rows of cells, outside of which lies the single row of arche- 

 sporial cells, and four rows of cells belonging to the wall of the 

 capsule. 



As the section is examined higher up, however, there are 

 marked differences, especially in the divisions of the arche- 

 sporium. The first divisions in the archesporium of Notothylas 

 are periclinal, and for a short distance it is two-layered, as it is 

 permanently in Anthoceros; but still further up it widens very 

 rapidly by the formation of repeated periclinal walls, and soon 

 comes to be much thicker than either the columella or the capsule 

 wall. A further study of the developing archesporium shows 



