140 BOTANICAL GAZETTE [AUGUST 
characteristic of Marchantiales (figs. A, B, C), the vertical median 
wall (1) 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 
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Fic. 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 
