78 



The ef,rly development of the tetras; ore-like struct\ire5 

 is siLiilar in every detail to corresponding sta,ges in the 

 development of tiie normal tetraspores. Small uniin\iclea,te 

 papillae are cut off from the ui>per "border of the vegeta- 

 tive cells. Each divides to form a short twO-celled "branchy 

 the lower cell repx^esenting the stalk cell of the tetra- 

 sporangian, the upper corresponding to the tetraspore 

 mother cell (figs. 145,146) . The stalk cell increases in 

 size and becomes vacuolate, the mother cell also becomes 

 larger, but reiiiains somev/hat smaller than the normal tet- 

 raspore mother cell. The average diameter of the fully 

 formed itiatiure mother cell is about 20-22 W as against 24 K 

 for the mother cell of the tetraspore. The nucleus in the 

 t.7o cases shov/s the sajne configuration, but remains smaller 

 in the mother cells borne on the sexual plant, (fig. 147). 

 ITuclear raa.terial passes out into tlie cytoplasm where it 

 forms small darkly staining granules, 



Involucral rays are formed in the v/ays chaj'acteristic 

 of the tetraspore-sorus, usvially as outgrowths from the 

 vegetative cell outside the ring of spore mother cells, 

 exceptionally as lateral outgrowths from the stalk cell 

 (fig. 148). 



The furtiier development of the mother cells on the 



