56 BOTANICAL GAZETTE [January 



Summary 



i. Two appendages may be present on the ventral scales. 



2. Rhizoids are absent among the first pairs of ventral scales. 



3. Old rhizoids are often replaced by new ones that form within 

 them. 



4. Fungi are prevalent in the compact tissue of the thallus. 

 They enter through the rhizoids and may also pass out through 

 them. No " pseudoparenchyma " was found. 



5. The secretion of mucilage seems to have nothing to do with 

 the "protection" of the growing point, but to be most pronounced 

 about the egg and the antheridia. 



6. Pitted cells show no tendency to become trachea-like. 



7. The origin of air chambers in the thallus and receptacles is 

 schizogenous. The horizontal increase in the size of the chambers 

 is due to a tearing of the tissues. The pore of the chambers of the 

 thallus and of the antheridial receptacle is simple, but that of the 

 archegonial receptacle has an elaborate margin. 



8. The development of the sex organs follows the Marchantiales 

 type. The archegonia form early in the history of the receptacle 

 and parallel the increase in size of the receptacle by great increase 

 in length of the neck. Following fertilization an exceedingly 

 massive venter is developed about the embryo. 



9. Five archegonia may begin to develop on one receptacle, but 

 no more than three come to maturity. 



10. The condition of the cells of the foot and of the adjacent 

 parts of the thallus indicate the parasitic nature of the sporogonium. 

 No elaterophore appears. 



Most cordial thanks are due Dr. W. J. G. Land, who furnished 

 the material for this study and followed the work with interest and 

 encouragement. 



Mount Holyoke College 



LITERATURE CITED 



1. Barnes, C. R., and Land, W. J. G., Bryological papers I. The origin of 

 air chambers. Bot. Gaz. 44: 197-213. 1907. 



2. Black, Caroline A., The morphology of Riccia Frostii. Ann. Botany 

 27:511. 1913. 



