BOTANICAL GAZETTE 



characteristic of Marchantiales digs. A, B y C), the vertical median 

 wall (i) is followed by two walls (2 and 3) at right angles to the 

 former, thereby forming quadrants {A, B, C, D). Four periclinal 

 walls (4, 5, 6, 7) form a sterile wall cell and a spermatogenous cell 



Fig. 1. — Explanation in text 



from each quadrant. In the Jungermanniales form (figs. D, E, F) 

 the median vertical wall is followed by two walls corresponding to 

 the second and third above, but somewhat inclined (2, 3, fig. E). 

 Periclinal walls (5, 7) form two centrally placed spermatogenous 

 cells. The quadrants A and C have become sterile wall cells; only 

 the quadrants B and D give rise to spermatogenous cells. In the 



