THE FUNGUS CAUSING ANTHRACNOSE. 31 



scald. It appears, however, to be widely and generally distributed 

 throughout the cranberry growing regions of the eastern United 

 States. 



THE FUNGUS ( GLOMERELLA RUFOMACULANS VACCINII, SHEAR) CAUSING 



ANTHRACNOSE. 



Two species of Gloeosporium have already been described as occur- 

 ring upon species of Vaccinium, but their relation to the fungus 

 causing this disease is doubtful. This parasite has been grown in 

 pure cultures, producing both the conidial and ascogenous forms. 



Conidial form. The acervuli are rather small, scattered over the 

 under or upper surface of the leaf and sometimes occurring upon old 

 berries which have been destroyed by the fungus. The epidermis is 

 usually somewhat dark colored immediately above and about the 

 mass of conidia. At maturity the epidermis ruptures and the conidia 

 form a light, flesh-colored, waxy mass upon the surface. They are 

 hyaline or subhyaline, as observed under the microscope, and oblong 

 elliptical, or sometimes slightly smaller at one end, varying in dimen- 

 sions from 12 to 18 by 4.5 to 6 /x (PL III, fig. 2). The conidiophores 

 are simple, tapering upward, and from 15 to 20 /x long. The conidia 

 germinate readily in water or ordinary culture media. The mode 

 of germination and growth agrees with that of other species of 

 Gloeosporium, as described by Stoneman, 45 Clinton, 46 and others, 

 except that no septum is formed in the conidia so far as observed. 

 This conidial form has been found on berries from several localities 

 in Massachusetts, and also on leaves from New Jersey which were 

 soaked in corrosive sublimate 1-1,000 and kept in a moist chamber 

 for from one to two weeks. It has also been obtained in cultures 

 made from diseased fruit from Wisconsin, Massachusetts, and New 

 Jersey. 



Ascogenous form. This stage of the fungus has not been found 

 on the cranberry plant either in the field or in moist chambers, but 

 has been grown in cultures from leaves bearing the fungus, and also 

 from ascospores. The perithecia are membranous, subglobose or 

 slightly pear shaped, usually somewhat buried in a felty subiculum 

 or pseudo-stroma when growing on corn meal and forming a continu- 

 ous layer over its surface (PI. Ill, fig. 6). In old cultures they fre- 

 quently become closely packed and form a more or less opaque stra- 

 tum. The asci are clavate, sessile, or short stipitate, and measure 60 

 to 72 by 10 to 12 /A (PL III, fig. 7, a, , <?), and are sometimes accom- 

 panied by what seem to be evanescent paraphyses (PL III, fig. 9). 

 The ascospores are somewhat irregularly biseriate, oblong elliptical, 

 and occasionally slightly inequilateral or curved. They are hyaline 

 no 



