EUPHYCOPHYTA 165 



to have been suppressed as the zooids give rise to a plethysmothallus 

 that bears new sporophytes. 



AsPEROCOCCACEAE : Asperococcus (aspero, rough; coccus y berry). 

 Figs. 92, 93 



The structure of the adult plant is essentially the same as that of 

 the two preceding genera except that the central filaments degene- 

 rate and the centre becomes filled with a gas. The fronds are simple 

 or branched and bear small superficial cells with sporangia and 

 mucilage hairs scattered over the surface in sori. The plurilocular 

 and unilocular sporangia occur on the same or on different plants. 



Fig. 92 Asperococcus hullosus. A, plant. B, unilocular sporangia 

 (X225). Cj plurilocular sporangia (X225). (A, after Oltmanns; 



B, C, after Newton.) 



the sori with unilocular sporangia containing sterile paraphyses in 

 addition. The principal interest of this genus is centred around the 

 life histories which have been studied by several workers in con- 

 siderable detail. In A. compressus the life cycle is simple, the zooids 

 from the unilocular sporangia germinating directly into a protone- 

 mal phase that later turns into small plantules ; these can reproduce 

 themselves successively by means of zoospores from both pluri- 

 and unilocular sporangia until the advent of favourable conditions 



