368 BOTANICAL GAZETTE [june 



I have had three points in view in studying this group: (i) To 



many 



a careful study of it. All the perfect stages of Glomerella that have 

 been found are very similar, and some writers have gone so far as to 

 say that there is only one species. There also seems to be a difference 

 of opinion as to the structure of the perfect stage, Glomerella was 

 described as aparaphysate, but recently Sheldon (39) has reported 

 the presence of paraphyses. Several forms have been studied to 

 obtain some evidence on this point. (2) To determine if the forms 

 of Gloeosporium found on apple represent a single species or more 

 than one. The true bitter rot fungus occurring on apples in the south 

 spreads rapidly and causes a great deal of damage, while the form 

 occasionally met with in the north spreads slowly and causes but 

 little damage. The form from the south produces pcrithecia in 

 abundance on various culture media; the northern form was studied 



Stoneman 



Clinton 



expressed surprise that she was unable to find them. (3) Can species 



of Gloeosporium be distinguished by culture methods ? Miss Stone- 

 man has attempted to find characters in this way that would help to 

 differentiate them. It is impossible to distinguish all the species by the 

 characters found on the hosts. The spores in many of them are ahke, 

 the acervuli vary but Httle, and the cross-inoculation experiments 

 that have been tried by various authors have proved but little. 



The following paper is based on work carried on with anthracnoses 

 from about thirty different hosts and from fifty or more sources. The 

 forms have been studied in the usual manner. They have been ob- 

 tained in pure cultures and studied in various artificial media as well 

 as upon the host. The structure of the acervuli, and of the perithecia 

 where found, has also been studied in thin. carefuUv stained microtome 



sections. Most of the material was fixed in Gilson's fixing solution.' 

 As is well known, the spores of Gloeosporium are imbedded in a gelat- 

 inous substance which is very soluble in water. If pieces of the 

 material are put in an aqueous fixative, as Flemming's or chrom- 

 acetic, the spores are almost entirely washed away. The gelatinous 



2 Gilson's fixing solution: 95 per cent, alcohol 42CC, water 6oc<:, glacial acetic 

 acid 18CC, nitric acid (cone.) 2<:c, corrosive sublimate (sat. sol.) ii<:c. The material 

 is left in the fixer 6-24 hours and washed directly in 70 per cent, alcohol. 



