276 



GRACE A. DUNN 



Fig. 1. A. Mature tetrasporic plant, showing type of branching and frayed 

 ends of branches. X 0.35. B. Diagram. Transverse section through thallus 

 showing distribution of tetraspores. X 250. C. Longitudinal section through 

 wall of thallus, showing origin and contents of mother cells of tetrasporangia, 

 t. m. c. X 700. D. Longitudinal section through mother cell of tetrasporangium 

 showing connections to the cortical cells at its outer end. X 1000. E. Surface 

 view of tetrasporangium, showing cj^toplasmic net, position and structure of 



