PBESENT INVESTIGATION". 13 



The conidial form of this genus of fungi is apparently much more 

 common, conspicuous, and likely to be observed than the perithecial 

 form. For this reason the majority of the species are much better 

 known in their conidial condition than in any other and have been 

 described principally under the names Gloeosporium and Colleto- 

 trichum, though some have apparently been referred to Cylindrospo- 

 rium, Marsonia, and other similar genera. Four hundred and 

 seventy-three species of Gloeosporium and Colletotrichum are given 

 by Saccardo. This does not, as already suggested, include all of the 

 species or forms that belong to this group, as some are found under 

 other generic names. On the other hand not all the forms or species 

 described under Gloeosporium and Colletotrichum are conidial 

 stages of Glomerella. 



It is quite certain, from a study of specimens and a comparison of 

 the descriptions, that about 50 per cent of these so-called species can 

 not be separated except on the basis of host relations or part of the 

 host attacked. No monographic treatment of Gloeosporium and 

 Colletotrichum has yet been attempted. The compilation of descrip- 

 tions undertaken by Ellis and Everhart (33), in the Journal of My- 

 cology, and that of Saccardo (67), in Sylloge Fungorum, are practically 

 all we have. 



Cross-inoculation experiments have been carried on at different 

 times by different investigators. Owing to the various methods 

 practiced in different cases and in some instances the lack of record of 

 sufficiently definite information as to the details of the work, it is 

 difficult satisfactorily to compare and coordinate the results. South- 

 worth (84), Halsted (39, 40, 41), Cobb (20, 21), Clinton (19), Burrill 

 (15), Edgerton (28, 29, 30, 31), Sheldon (77, 79), Chester (18), and 

 Taubenhaus (90, 91) have made the principal contributions to this 

 phase of the subject. A discussion of these results accompanied by 

 tables will be found on subsequent pages. 



Considerable attention has already been given by different investi- 

 gators to cultural and life-history studies of these organisms. Among 

 these may be mentioned the work of Southworth (84, 85), Atkinson 

 (2), Stoneman (89), Clinton (19), Edgerton (28, 29, 30, 31, 32), 

 Lasnier (55), von Schrenk and Spaulding (70), Sheldon (77, 78, 79 ; 

 80, 81), Shear (74), Barre (7, 8), Shear and Wood (75, 76), Koorders 

 (54), and Scott (73). The work of Klebahn (51, 52) on Gloeosporium 

 relates to species which are not congeneric with Glomerella. 



PRESENT INVESTIGATION. 



The present investigation was commenced by the senior writer in 

 1904. A brief summary of the early part of the work was published 

 by the present writers (75) in 1907. At that time the life histories of 

 the forms of Glomerella found on eight different hosts were briefly 



252 



