SECT. n. 



RHODOSPERMS. 



229 



cences, immersed either partially or wholly in 'some part 

 of the frond. 



The simple spores are produced within colourless 

 tubercules called nuclei, variously situated upon the 

 plant, as at fig. 23 a, c. These nuclei contain many mi- 

 croscopic spores. Sometimes the nuclei are enclosed in 

 conceptacles or ovate sacs, which are either perforate 

 or not at the apex. These contain many microscopic 

 strings of cells like jointed threads, and the endochrome 



Fig. 23. A, Polyides rotundus : a, thin slice showing the wedge-shaped spores ; b, tetra- 



spores, 



B. Furcellaria f astigiata : e, thin slice showing a nucleus with the dividing spores ; 

 d, one of the large cells ; e, a tetraspore. 



in each joint of these threads is converted into a spore 

 successively from the summit downward. Sometimes the 

 endochrome in one or two joints only, becomes a spore 

 whether terminal or central, and when the spores break 

 through the joint wall and fall off from the threads, they 

 are collected without any definite order into a mass 

 within the nuclei. Sometimes new joints or cells are 

 produced on the threads when the old ones have 

 yielded their fruit. Occasionally a globose nucleus 

 contains several secondary nucleoli full of spores. In 



