194 Transactions British Mycological Society. 
disease was based upon a mixture of forms. In America it has 
been shown by Rosenbaum and Sando* that Macrosporium 
tomato Cke. may be the cause of a disease of uninjured tomato 
fruits. 
Series 4. 
This includes the forms K, K 2, and S with the authenticated 
culture of Colletotrichum phomoides (Sacc.) Chest. (Form D). 
As has been noted by Shear and Wood (15 P. 64) in dealing 
with the ascomycetous genus Glomerella, the conidial stage 
(Gloeosporium or Colletotrichum) shows great variability in its 
mode of formation and in morphological characters. In some 
cultures the conidia are borne on scattered conidiophores and 
in others large compact acervuli occur. Later these authors 
point out that setae are also a variable factor, being entirely 
absent in some cultures and present in others. 
This variability was also noted by us in the four forms studied, 
and again, as in Series No. 2, makes the taxonomic arrangement 
of the forms very difficult. 
In comparing the forms K, K 2, and S with the authenticated 
culture (D) of Colletotrichum phomoides (Sacc.) Chest.(3) it was 
found that form S was identical with the latter, except that 
setae were not always produced in artificial media, although 
when transferred to tomato fruits setae were abundantly formed. 
The acervuli varied from 180-360 » in diameter and the conidia 
were borne at the apex of short branched conidiophores. The 
conidia were usually cylindrical with rounded or slightly pointed 
ends, very regular in shape and size, and always unicellular. 
The cell contents were very granular. 
The great majority of conidia were uniform in size at 21 4x4 p, 
though conidia were seen varying between 14m to 24p x 3p 
to 4:5. This form can therefore be undoubtedly diagnosed as 
Colletotrichum phomoides (Sacc.) Chest., and is, we believe, its 
first recorded appearance in England. 
The forms K and K 2 were identical one with the other but 
both slightly differed from forms D and S, since, on artificial 
media large compact black acervuli were very seldom formed, 
the conidia being borne on cushion-like loose aggregations of 
conidiophores. Spore-formation seemed to be much more pro- 
fuse than in the other forms, as the spores were produced in 
such abundance that the whole surface of the fruit was covered 
with pink masses of conidia almost coalescing one with another. 
Some conidia were very slightly curved; they were all non- 
septate, very uniform in size and vacuolate. Setae were not 
observed. The size of the conidia in K varied from 19 to 
* Rosenbaum, J. and Sando, C. E. Correlation between size of fruit and its 
relation to infection with Macrosporium tomato. Amer. Journ. Bot., 1920. 
