5o8 ■ The Ohio Naturalist. [Vol. VI, No. 6, 



by the fungus by the time of flowering, develop pods in propor- 

 tion to their vigor. The pods are badly attacked and exhibit 

 spots quite similar to the ordinary anthracnose of the bean. In 

 a case of Ascocyhta pisi on Egyptian-peas, Lochhead^ describes 

 the spots on pods to have "rings of black specks more or less 

 concentric." No such appearance was found in connection 

 with any of the peas examined. However, the Egyptian-pea 

 belongs to a different genus from any host found by the writer 

 to be aiffected with Ascochyta pisi. 



Perhaps the most important thing in connection with the 

 life history of the fungus, is, that it grows through the husk into 

 the seed. Frequently, when the pod contains no seed, the my- 

 celium will grow through, forming similar spots on both sides of 

 the pod. When the mycelium passes into the seed, brown spots 

 are formed on the surface. In the worst cases, half of the sur- 

 face is frequently discolored and the seed adheres to the husk.. 

 These areas are much more striking on green peas such as the 

 Market Garden than on the yellowish varieties as the Admiral. 

 Peas affected with the mycelium of the fungus, can not always 

 be told by an ordinary microscopic examination. A consider- 

 able amount of mycelium sometimes fails to color the pea and no 

 spot is developed until the pea is exposed to considerable mois- 

 ture for a short period. 



The fungus. — The pycnidia of the fungus are formed on the 

 dead arenas of the stems, leaves, pods and seed and even on dead 

 stems and branches where the effects of the fungus are not easily 

 noticeable. They are ordinarily brown, have a circular opening 

 and measure 125 to 160 /* in diameter. On the seed, they are 

 formed on the outer surface, but frequently this is cracked away 

 and fruit bodies occur below. Here they are often of a yellowish 

 or amber color and occur in numbers from a few to several 

 dozen and are sometimes so crowded as to form almost a solid 

 mass for as much as five or six mm. in diameter. 



The spores are oblong, usually 2-celled and slightly constricted 

 at the septum. Those of the field-pea (French June), measured 

 12 to 16 X 4 to 6 /u,. One measurement of spores on pea seed 

 showed them to be 8 to 1 1 x 5 to 7 /«. and practically all con- 

 tinuous; while those on a specimen of Market Garden seed, were 

 1,0 to 20 x 3 to 5 ju. and a few, even, were 2-septate, measuring 

 as much as 23 /x long. Lack of maturity was the chief cause 

 of the continuous spores, though some of these never become 

 .septate. Lochhead^ reports only a few 2-celled spores found in 

 some material of Egyptian-peas affected with Ascochyta pisi. 

 Ascochyta pisicola (Berk.) Sacc, which is perhaps identical with 



3. Ont. Akt. Coll. and Exp. Farm. An. Rep. lilO.'J, pp. 17-33, figs. 13. 



4. Lochhead, 1. c, p. 27. 



