40 GENUS PALLAVICINIA 



7. Of the three species examined, P. Zollinger! has the smallest 

 archegonial receptacle, and P. radiculosa the largest. The archegonium 

 of P. radiculosa shows a limited apical growth due to the activity of the 

 cover-cells. 



8. The embryo of Pallavicinia agrees in many ways with that of 

 other Anacrogynae that have been studied. It is perhaps most like that 

 of Aneura in the development of a very large haustaurial organ, or sus- 

 pensor. In this respect the species under consideration seem to differ 

 a good deal from P. decipiens, and from Morkia. Of the three species, 

 P. Zollingeri is nearest to Morkia in the form of the capsule and the larger 

 foot. 



9. The species all agree in the structure of the capsule, which has 

 a more or less conspicuous terminal beak or pad, which remains intact, 

 so that the four valves of the open sporogonium remain attached to each 

 other at the apex, and the capsule opens by four longitudinal slits. The 

 beak is best developed in P. radiculosa, which has a much more elongated 

 capsule than the other species. In its much shorter and relatively broader 

 capsule, P. Zollingeri is more like Morkia or Calycularia. P. Zollingeri 

 is also like the latter in the tuberculate spores. In P. radiculosa and P. 

 Levieri the spores are reticulately marked. 



