20 GENUS PALLAVICINIA 



of P. Levicri were much longer than those of either of the other species 

 that were studied, sometimes reaching a length of a centimeter or more 

 The archegonial receptacles are smaller than those of P. radiculosa. and 

 are more like those of P. Zollingt 



The Antheridium 



Of the three species examined. /'. nidiculosa \va* the best for the 

 >tudy of the young antheridium. as most of the stages of development 

 were found in the mat> 



Fig. 10. Pallavicinia radiculosa. 



Early stages in the development of the antheridium. 

 Longitudinal sections. D, F, are cut in a plane at right angles to E, G. 





