CALYCULARIA RADICULOSA CAMPBELL 



55 



tions were made were already far advanced and were differentiated into 

 the various parts. 



Even before the first division takes place in the young embryo, the 

 venter of the archegonium becomes much enlarged, and a calyptra is devel- 

 oped, enclosing the sporogonium until it is far advanced. This attains a 

 thickness of 5 or 6 layers of cells at the base, but is much thinner toward 

 the apex. As the sporogonium develops, the upper portion or capsule 

 becomes oval in form, and below consists of a thick seta, which terminates 

 in a large heart-shaped foot very much like that which Cavers describes for 

 Morkia Flowtowiana. (Cavers Loc. cit. Fig. 37). A similar foot has been 

 observed in various other Jungermanniales. 



:B 



el 



Fig. 10. A, median section of a sporogonium at the time of the mitosis of the 

 spore mother cells, x 15. B, apical region of a younger sporogonium, sp. spore 

 mother cells, el. young elator, x 225. C, part of the lateral wall of the sporogonium. 



The capsule (Fig. 10) has a relatively thick wall which is better de- 

 veloped at the apex than at the sides, this difference becoming still more 

 marked in the later stages. The inner tissue now shows a separation into 

 the roundish spore mother cells and the elongated young elaters. Long 

 before the division of the spore mother cells begins, they show the first indi- 

 cations of the lobing which later becomes so conspicuous. At this stage the 

 walls of both the spore mother cells and the elaters are very delicate, but 

 can be readily demonstrated by suitable stains, e. g. Bismarck brown. 



