September 20, 1907] 



SCIENCE 



385 



PRELIMINAEY NOTE ON A NEW DISEASE OF THE 

 CULTIVATED VETCH 



About the middle of last July the senior 

 author discovered a fundus disease of the 

 cultivated vetch which does not seem to have 

 been reported before. He first observed it on 

 the stems and pods from a small patch of the 

 vetch on the horticultural grounds of Cornell 

 University. It was later brought into the 

 laboratory from two fields of the cultivated 

 vetch on the university farm. The disease 

 appears to be quite abundant and is often as- 

 sociated with an Ascochyta, especially on the 

 stems. Here the two fungi are often mixed 

 together and it is thus possible for one not 

 familiar with the new one to confuse its spores 

 with those of the Ascochyta. On the pods it 

 often occurs quite pure, and here it is easily 

 seen with the unaided eye to be quite distinct 

 from the disease caused by the Ascochyta. It 

 is, however, frequently mixed even on the 

 pods with the Ascochyta, but the spots are 

 here so characteristic that there is no trouble 

 in distinguishing it. 



The gross appearance of the spots and spore 

 pits on the pods is very striking. The spots 

 are elongated, forming either long narrow or 

 elliptical spots, sometimes with a dull purple 

 border. The spots on the pods are oblique, 

 probably due to the oblique fibrous structure 

 of the pods. The middle line of the spot is 

 white from the numerous spores formed on 

 the basidia and which later ooze out in masses. 

 When in mass the spores have a pale pink or 

 flesh color, and a hasty preparation suggests 

 the genus Glososporium. When the spores are 

 washed by the rains they give a whitish ap- 

 pearance to the entire spot because of the 

 thinness of the layer. 



The fruiting part of the fungus is beneath 

 the epidermis, the latter being ruptured in the 

 form of a slit through which the spores escape. 

 The mycelium becomes brown and then 

 black, and the epidermis is also blackened by 

 the action of the fungus. In age then the 

 spots are black oblique lines as seen on the 

 pods, and many of them may be sterile 

 through failure of the fungus to fruit. 



The spots caused by the Ascochyta are 

 nearly or quite circular, grayish in color, with 



a dull purple border, and the grayish center 

 punctate with the minute brownish pycnidia. 



Besides the interesting character of the 

 spots the structure of the fungus causing this 

 new disease of the vetch is even more interest- 

 ing. In structure it resembles that of a spe- 

 cies of Corticium. The basidia form a definite 

 hymenium which arises from the pseudopar- 

 enchymatous subhymenium of angular cells, 

 two to three cell layers in thickness. The 

 nourishing mycelium extends out into the sur- 

 rounding tissue of the host. The basidia bear 

 four to eight spores, which are sessile and 

 usually produced in a whorl or crown at the 

 end. The spores are oblong to subelliptical, 

 straight or curved, continuous, hyaline, granu- 

 lar, and measure 12-20 x 3-3.5 /x. As the 

 spores fall away from the basidia others are 

 probably produced (in culture they are). 

 Conidia similar to the basidiospores are pro- 

 duced on slender conidiophores. These are in- 

 termingled with the basidia and this character 

 recalls that of the genus Exoia-sidium. The 

 spores also bud in yeast-like fashion from one 

 or both ends, rarely from the side, and the 

 sporidia thus produced are similar to the 

 spores. In this way a great mass of spores is 

 produced from the spore pit. The fungus oc- 

 curs on the leaves and flower bracts also. It 

 has been obtained in pure culture by several 

 different methods of separation. It grows 

 slowly, but ultimately produces numerous 

 black stromatic bodies and numerous spores, 

 which are pink in mass. 



The fungus appears to be the type of a new 

 genus for which the name Protocoronospora 

 is proposed, and a provisional diagnosis is 

 given as follows : 



Protocoronospora Atkinson and Edgerton 

 new genus. 



Stroma pseudoparenchymatous, two to three 

 cell layers in thickness, formed by the com- 

 pact branching of the mycelium, the ultimate 

 exterior branches producing the basidia which 

 form a hymenium. Spores sessile, hyaline, 

 colorless, continuous, smooth, several (usually 

 four to eight) on a basidium. Spores budding 

 and forming sporidia similar in form. Coni- 

 dia also similar in form on slender short 

 conidiophores intermingled with the basidia. 



