V] 



LABOULBENIALES 



173 



monoecious forms) bears the appendages in a terminal position and the 

 perithecium laterally (fig. 136). 



More rarely the receptacle consists of a larger number of cells variously 

 arranged and reaching a considerable complexity in such forms as Zodio- 

 myces vorticellarius (fig. 133). 



One or more appendages are borne on the receptacle. These are more 

 or less filamentous and often elaborately branched. They bear the male 

 organs and serve also for the protection of the delicate trichogyne and perhaps 

 facilitate fertilization by holding a drop of water around the organs con- 

 cerned. The primary appendage is developed from the upper segment of 

 the germinating spore and is terminal ; the later formed secondary append- 

 ages, when present, are outgrowths from the cells of the receptacle. 



The male element is a non-motile cell which as early as 1896 was 

 homologized by Thaxter with the spermatium of the Red Algae. The 

 latter organ has now been shown to be an antheridium' in which the 

 nuclear divisions are reduced to one, or have altogether disappeared ; it is 

 liberated entire from the male plant and carried passively to the female 

 organ. It seems very probable that in the simplest cases, where they are 

 produced externally at the tips of more or less specialized branches (fig. I34)> 



Fig. 133. Zodiovtyces vorticellaritis 'XXiz.yA&x ; 2itzx 

 Thaxtev. 



Fig. 134. Ceratomyces rostra' 

 tus Tliaxter ; exogenous 

 spermatia ; after Tliaxter. 



^ Wolfe, Ann. Bot. xviii, 1904. Yamanouchi, Bot. Gaz. Ixii, 1906. 



