24 Brannon. — The Structure and Development of 



frond from small portions which have been cut from the 

 parent plant. 



7. It is found by experiment that the carpospores and 

 tetraspores are excellently adapted to the studyof the various 

 phenomena attending germination, for while they respond 

 readily to change of intensity of light, temperature, and salinity 

 of the surrounding water, yet they are sufficiently hardy to 

 develop into young plants when artificially supplied with 

 favourable conditions. 



8. The non-motile antherozoids are developed in enormous 

 numbers by the abstriction of the terminal portion of the 

 apical cells of the antheridia. 



9. The cystocarp begins to develop by the modification 

 and apical growth of a joint-thallus-cell. 



10. The procarp, consisting of three cells, is developed froni 

 the supporting thallus-cell in the base of the young cystocarp. 

 Its apical cell becomes the carpogonium. Subsequently, the 

 fertilized contents of the carpogonium are transferred through 

 the open pores connecting the procarpic cells to the sup- 

 porting thallus-cell which becomes the central one of the five 

 auxiliary cells. 



IT. The trichogynes are often branched, and as many as 

 five simple ones may grow from a cystocarp borne on a 

 proliferation. 



I a. Fusion of the antherozoid with the trichogyne results 

 in great stimulation to the thallus-cell at the base of the 

 procarp, and rapid disintegration of the trichogyne, which is 

 a very evanescent organ. 



13. The sporiferous filaments are developed as chains of 

 central cells, from each of which a whorl of spore-producing 

 threads may originate. 



14. The carpospores arise acropetally from the branches 

 of the sporiferous filaments, and not interstitially. 



15. The development of the cystocarps of Grinnellia agrees 

 with that reported for Gracilaria in that the body-cavity 

 develops schizogenetically, and that the sterile filaments 

 connect the pericarp with the cortical tissue belgw the group 



