CONTINUED: CLASSIFICATION. 



173 



cluster called the sporocarp, which means spore-fruit or spore-fruit body. 

 In Batrachospermum it is seen as a compact tuft in the loose branching, in 

 Nemalion it lies in the surface of the cortex, while in Lemanea the sporo- 

 carps lie at different positions in the hollow tube of the sexual shoot. 



376. Gonidia in the red algae. The common type of gonidium in the red 

 algae is found in the tetraspores. A single mother cell divides into four cells 

 arranged usually in the form of tetrads within the tetrasporangium. In 

 Callithamnion the tetrasporangium is exposed. In Polysiphonia, Rhab- 



Fig. 184. 



A red alga (Callithamnion), showing spor- 

 angium A, and the tetraspores discharged 

 B. (After Thuret.) 



tig. 185. 



Gracilaria, portion of frond, 

 showing position of cystocarps. 



Fig. 186. 



Gracilaria, section of cysto- 

 carp showing spores. 



donia, Gracilaria, etc., it is imbedded in the cortex. In Batrachospermum 

 there are monosporangia, each monosporangium containing a single goni- 

 dium, while in Lemanea, and according to some also in Nemalion, gonidia 

 are wanting. 



