32 



GENUS PALLAVICINIA 



beginning of the capsule, or sporogenous region. It was not possible to 

 determine the relation of the three regions of the young sporophyte, i. e., 

 capsule, seta, and foot, to the early divisions in the terminal cell of the 

 embryo. 



Fig. 1 8. Pallavicinia Z oiling eri. 



A. Upper part of a young sporophyte, x 300. 



B. Upper part of an older sporophyte, showing the sporogenous tissue ; x about 60. 



C. Portion of B, more highly magnified. 



In P. decipiens the young embryo is much shorter than in either 

 P. Zollingeri or P. radiculosa, and more nearly resembles that of Morkia, 

 although more elongated than in the latter. Like Morkia, also, the sus- 

 pensor is much less conspicuous than in either P. Zollingeri or P. radicu- 

 losa. 



The first periclinial walls in the terminal portion of the embryo 

 probably determine the separation of the sporogenous tissue from the 

 wall of the capsule (Fig. 16, E). The foot is much less clearly marked 

 than in Morkia, but is more evident in P. Zollingeri than it is in P. radicu- 

 losa; nor is the delimitation of the capsule and seta as definite as in either 

 P. decipiens or Morkia. 



Of the three species examined, P. Zollingeri most nearly resembles 



