iqi 7 ] DUNN—DUMONTIA 445 



distinguish the structure of their contents. The cytoplasm in all 

 the trichogynes with the spermatia attached to them appeared to be 

 disintegrated, and no trace of a male nucleus was seen in any of 

 them. Disintegrating cytoplasm stains very deeply in vegetative 

 cells which have been injured, in trichogynes which have functioned, 

 in carpogonial branches which have not been fertilized but are 

 destined soon to disappear (fig. 36), and in those cells of the auxiliary 

 cell apparatuses which are terminal and will also soon disappear. 

 The cytoplasm of the trichogyne would not disintegrate as soon as 

 the male nucleus had entered it, so that this nucleus in all these 

 cases had probably passed into the carpogonium. Only one sper- 

 matium was attached to each of the other 3 trichogynes. 



It has always been extremely difficult to obtain clear evidence 

 concerning the phenomenon of fertilization in the Florideae. A 

 few workers, as Oltmanns (9), Osterhout (ii), Hassencamp 

 (3), Wolfe (19), Yamanouchi (20), and Svedelius (16) have suc- 

 ceeded in finding consecutive stages showing the fusion of the 

 spermatium to the trichogyne, the passage of the male nucleus down 

 the latter, and the fusion of the male and female nuclei in the carpo- 

 gonium. The only two members of the Dumontiaceae in which 

 the structure of the female reproductive organs has been care- 

 fully worked out are Dudresnaya purpurifera and D. coccinea 

 (Oltmanns 9). Oltmanns in D. purpurifera observed the entrance 

 of the male nucleus into the trichogyne. The nucleus of the car- 

 pogonium at this time has moved out into the coiled portion 

 of the trichogyne. No nucleus is present in the trichogyne in the 

 next stage which he observed, but in the carpogonium there is a 

 nucleus which he assumes to be the fusion nucleus. Oltmanns 

 states that he was not able to secure satisfactory evidence concern- 

 ing the fusion of the male and female nuclei. He does not describe 

 or picture fertilization in Dudresnaya coccinea, but states that it is 

 in no way unusual. In Dumontia less evidence has been obtained 

 concerning fertilization than Oltmanns presented in the discussion 

 of the two species of Dudresnaya. Nevertheless, there is really no 

 reason to doubt the occurrence of fertilization in these forms. 



As previously stated, the mature carpogonial branch is always 

 bent around so that the carpogonium is close to or in actual contact 



