NORTH AMERICAN PARASITIC EX()A.SCP:.E. loi 



T.he follovvino" references include specimens on \'arious 

 hosts and it is impossible to determine with certainty to what 

 species of the present classification they should be referred. 



I5esst'\' '85. Webber ''/>. 



(jaliowiiy '89, llalsted '(jjf/. jij). 



I lalsted '92/'. pp. 



Da\ is '93. 



ExoAscus COMMUNIS Scidchcck. Plate I. I'^ig. 2. 

 Bibl. and Syn.: 



Iixoasnts pniiii Auct. x\mer. pp. 



Kellermaii 'S^tr Peck '86. 



Kellerman '85/^. Pilellerman ^^ Carleton "87. 



Smith & Panimel. 



Tciplin'iia priiiii K\\\zt. x\mer. pp. 



Robinson '87. Ellis tV E\ erhart. 



James '88. .Seymour tV Earle '93. 



Exoasciis coiinniiii/\< Sadebeck "93. 



The microscopic appearance of fruits affected b\- this species 

 is very similar to that of those suffering from the presence 

 of E. -pniiil just described. The asci are densely packed 

 together, rather slender and club-shaped with the upper ends 

 rounded or truncated 30 40;^ in length, 34" in diameter. 

 The stalk-cells are 15-20// high, more slender than the asci 

 and somewhat pointed at the ends; the}' do not extend 

 between the epidermal cells. The size of the asci and the 

 size and shape of the stalk-cells are quite different, it will be 

 observed, from those of E. -pnini. The spores are ball- 

 shaped or oval 3-4" in diameter, normally eight in number, 

 but frequently the asci are tilled with conidia. This species 

 occurs upon Pninns aiiicn'caua, P. iiiaritiina. P. pniiiila, P. 

 nigra, P. suh-cordatiu and the De Soto plum a cultivated 

 variety of /-*. aiiicn'caua. Upon these hosts it causes the for- 

 mation of pockets or bladders usually after the fall of the floral 

 envelopes. The specimens I examined upon P. aiiicricaua 

 were collected in Wisconsin bv Mr. A. B. Sevmour. in Kansas 

 bv W. A. Kellerman. in Iowa bv L. O. Williams and Dr. A. 



