18 CEANBEEKY DISEASES. 



The fifth successful culture from diseased berries was made May 

 10, 1904. The berries Avere received from Cranmoor, Wis. They 

 Avere softened and shriveled and showed definite black spots on the 

 surface. After washing and soaking for three-fourths of an hour 

 in corrosive-sublimate solution, sections of the diseased portion, in- 

 cluding the skin, were transferred to large' tubes of sterilized corn 

 meal. About one month later ascogenous perithecia of Guignardia 

 Avere found in this culture. Several other cultures made at the same 

 time upon the same culture medium and from fruit having the same 

 appearance produced only pycnidia. Transfers made from cultures 

 producing asci to sterile potato cylinders have produced the ascoge- 

 nous form as quickly and abundantly as when grown on corn meal. 



Besides the successful cultures just described, Avhich haA'e been made 

 from diseased berries. Ave have, in three instances, obtained from 

 cranberry leaA'es pure cultures bearing both pycnidia and asci. 



On March 28, 1905, cultures Avere made by placing in flasks of 

 sterile corn meal leaA'es which had been first soaked for about one 

 hour in a 1 to 500 solution of corrosiA'e sublimate and then cut in 

 two i^ieces. These leaA^es Avere taken from A'ines which had borne 

 A'ery badly scalded fruit during the previous season. The vines Avere 

 collected on November 29, 1901. and kept in an ice box from that 

 time until the cultures Avere made. The leaA'es Avere of 1903 growth 

 and Avere to all external appearances healthy and free from fungi. 

 Leaves taken from this collection in ]\Iarch, 190G, still produced plenty 

 of good pycnidia and ascogenous perithecia. The course of dcA'elop- 

 ment of the fungus in these cultures was identical Avith that described 

 in the other cases. Pycnidia Avere produced in abundance in about 

 fifteen days, and at the end of tAventy-nine days ascogenous perithecia 

 were found in three of the cultures. 



From these original cultures mauA' others haA'e been made by trans- 

 fer. Four generations haA'e been groAvn in this way, producing both 

 pycnospores and ascospores in each. After this the fungus api^eared 

 to haA'e lost its vitality and did not grow Avell. In other cases it 

 developed both spore forms for one or two generations only. 



The fresh pycnospores of this fungus germinate and grow readily 

 in water, in a dilute solution of sugar and Avater, and in ordinary 

 culture media. Spores placed in a drop culture of sugar Avater in the 

 laboratory began to show signs of germination at the end of two daA^s. 

 The germ tube usually arises from the side of the pycnospore. first 

 forming a slight enlargement, which rapidly elongates into a germ 

 tube and soon begins to branch (PI. II, figs. 4 to 9). At the end of 

 four days many of the germ tubes haA'e attained considerable length. 

 The tube occasionally arises from the basal end of the spore (PI. II, 

 fig. 6), but Ave have never seen it arise from the apical end, Avhere the 



110 



