

456 BOTANICAL GAZETTE [june 



An examination of scores of young female plants has shown that 

 the trichogynes must persist for only a short time after they have 

 reached the surface of the thallus. Under these conditions an 

 arrangement whereby the fertilization of one carpogonium would 

 make possible the development of 3-6 cystocarps would evidently 

 be of considerable advantage to the plant. If the auxiliary cell 

 branches are carpogonial branches which have ceased to function, 

 Dumontia presents a case quite parallel to that of Corallina. In 

 Corallina (Oltmanns 10) only those carpogonia in the center of the 

 conceptacle which bear long trichogynes are capable of being 

 fertilized. The carpogonia at the periphery of the conceptacle 

 cannot be fertilized because they bear no trichogynes. In each 

 conceptacle often only one carpogonium is fertilized. Descendants 

 of the fusion nucleus in this one carpogonium pass to the auxiliary 

 cells of many procarps, and several cystocarps develop in one 

 conceptacle. 



Cell 2 or 3 of the carpogonial branch of Dumontia probably 

 functioned as the auxiliary cell before the plant had acquired 

 the habit of forming sporogenous filaments. It is cell 2 or 3 of 

 the auxiliary cell branch which forms the carpospores. One of the 

 3 cells in the carpogonial branch of Dudresnaya coccinea with which 

 the sporogenous filaments fuse, before passing to the auxiliary cell 

 branches, at one time probably functioned as the auxiliary cell. 

 The sporogenous filament often fuses with the fifth cell of the 

 carpogonial branch and with the fifth cell of the auxiliary cell 

 branch. In both Dumontia and Dudresnaya coccinea y therefore, 

 that which is supposed to have been the original auxiliary cell and 

 that which now functions as such occupy similar places in their 

 respective branches. The families of the Cryptonemiales show a 

 considerable variation in the distribution and structure of their 

 auxiliary cell and carpogonial branches. Even the species in one 

 genus as Dudresnaya (Oltmanns 9) may vary greatly in this respect. 

 It would then be rather surprising to find that the history of the 

 development of the auxiliary cells in all the Cryptonemiales is 

 similar. Oltmanns (9) suggests that the sporogenous filaments of 

 the Cryptonemiales have been developed from the gonimoblast 

 filaments of such forms as Wrangelia and Naccaria. He considers 



