1914] FROMME—AECIDIUM CUP 25 



seems 



the hymenium determine the relative numbers of peridial cells of 

 peripheral and interior origin. If the cup is shallow and the fertile 



number 



be com 



%• 7)- 



Hyd\ 



am aware, no estimate of the approximate number o 

 3d in an aecidium cup has been made. A compara 

 3 estimate of the number nroduced in the aecidium o 



made 



median 



mature 



numb 



found was 32. Since the cup is circular in cross-section, its radius 

 would be 16 and the area of the cross-section 804. 24. The average 



■ 



number of spores per chain (10), multiplied by the number of spore 

 chains (804. 24), gives a total production of 8042 spores. The esti- 

 mate of 10 spores per chain is low, since the count was necessarily 

 made before the opening of the cup, and the production of spores 

 probably goes on for some time after this. 



Wolf (29) has recently called attention to the production of 

 internal aecidia of P. angustata on Lycopus virginicus. These were 

 found principally in sections of stems and petioles. The cups are 

 very deep-seated, and being unable to reach the epidermis discharge 

 their spores into the parenchyma or the pith cavity. No internal 



of leaf tissue. 



my 



spermogoma 



in P. Claytoniata. These were buried at considerable depth in the 

 parenchyma of the stem, but were normal in other respects. The 

 spermatia had been discharged in some cases and were found in the 

 intercellular spaces above the ostiole. Still more curious were 

 several cases of intimate association between spermogonia and 

 aecidia in which the spermogonium was borne in the center of an 



aecidium. None 



© 



spermogonia 



abundance. The condition is evidentlv abnormal 



gonium and aecidium 



sper mo- 

 It does 



