462 BOTANICAL GAZETTE [june 



t 



the fusion nucleus in the carpogonium. The sporogenous filaments 

 grow out toward the auxiliary cell branches. The auxiliary cell 

 branches in origin, distribution, structure, and mode of develop- 

 ment are very similar to the carpogonial branches. Only about 1 

 auxiliary cell branch is initiated to every 7 carpogonial branches. 

 The time of initiation of the former is a little later than that of the 

 latter. The mature auxiliary cell branch consists of 4-7 cells. 

 The second or third cell of the branch is the auxiliary cell, the cell 

 with which the sporogenous filament fuses and the one which forms 

 the carpospore. The original nucleus in the auxiliary cell takes no 

 part in the formation of the carpospores. The nuclei in the car- 

 pospores are descended from the nucleus which enters the auxiliary 

 cell from the sporogenous filament. 



In the development of the carpospores and cystocarps 3 or 

 4 gonimoblast filaments arise from the auxiliary cell. Every cell 

 of these filaments forms a spore. There are about 20 carpospores 

 in each cystocarp. The pericarp is formed by radial branches 

 similar to those which form the subcortex and cortex of the wall 

 of the thallus. Mature carpospores are usually uninucleate, well 

 filled with a cytoplasm, and contain chromatophores. The chro- 

 ma tophores are similar to those of the vegetative cells. The nu- 

 cleus sometimes divides just as the carpospore is about to escape. 

 Naked carpospores escape through a pore formed in the pericarp. 

 Carpospores sometime germinate while in the cystocarp. The 

 ends of branches of mature plants fray, and this disintegration of 

 cells surrounding the cystocarp furnishes one means of escape for 

 the carpospores and sporelings. 



In the resting nucleus of Dumontia all the chromatin is in the 

 nucleolus. The nucleolus often contains a vacuole. The chro- 

 matin in preparation for mitosis passes out of the nucleolus and in 

 the form of small granules becomes distributed along the linin net. 

 The net disappears and the granules become massed together to 

 form larger units, chromosomes. The number of chromosomes was 

 not definitely determined, but was apparently about 7. No spi- 

 reme or spindle was seen. After division, the chromatin is again 



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found massed together in the nucleolus. 



Johns Hopkins University 



