196 Transactions British Mycological Society. 
SUMMARY. 
Various rots of tomato fruits and certain diseases of the 
stems of tomato plants have been investigated. These fruit rots 
commonly occur both on imported and upon home-grown fruit, 
and are caused by several different fungi about the identity of 
which there has been much uncertainty. The fungi isolated from 
rotten tomatoes have been compared with authentic cultures 
of certain presumably identical or closely related fungi from the 
United States. One of the rots is caused by Phoma destructiva, 
the British form of which is identical with that from America. 
Another of these rots is produced by a fungus which has hitherto 
passed in this country under the name of Mycosphaerella ct- 
trullina, but which is certainly not identical with the American 
fungus of that name. The British fungus which has hitherto 
been mistaken for this and which causes tomato stem “canker”’ 
as well as a fruit rot, appears to be identical with Diplodina 
Lycopersict Hollés which name also replaces Phoma Lycopersici 
Cooke. It has been considered advisable to amplify Hollds’ 
description and the fungus is therefore named Dzplodina 
Lycopersict (Cooke) Hollés, emend. Brooks and Searle. Another 
pycnidial fungus, found only once as the cause of a tomato rot, 
is associated with an Alternaria stage, and the name proposed 
for this fungus is Phoma alternariaceum Brooks and Searle. 
Finally, various strains of Gloeosporium and Colletotrichum 
parasitic on tomatoes have been isolated. One of these fungi 
is identical with the American Colletotrichum phomoides (Sacc.) 
Chester, and probably all of these forms are thus best grouped. 
The desirability of undertaking cultural sudies of fungi be- 
longing to such genera as Phoma, Diplodina, and Colletotrichiwm 
as an aid in the diagnosis of species, is emphasised. 
POSTSCHRIPAS 
Since this paper went to press, Petrak, in a note ‘“‘ Uber die Schwarzfaule 
der Tomaten”’ (Annales Mycologici, 1921, p. 17), describes a fungus occurring 
on the leaves, stems, and fruits of the tomato, which he considers identical 
with Plowright’s Phoma destructiva, but which he now names Diplodina 
destructiva (Plowr.) Petrak, because of the uni-septate character of the pyc- 
nospores formed on the leaves and stems although the spores are almost en- 
tirely non-septate in pycnidia on diseased fruits. Petrak’s survey of the litera- 
ture on this and allied tomato diseases is very incomplete, and, in the absence 
of inoculation and cultural experiments, it is by no means certain that he was 
dealing with one fungus only. As pointed out in our paper, it is doubtful 
whether a sharp line can be drawn between Phoma destructiva (Plowr.) 
C. O. Jamieson, and Diplodina Lycopersici (Cooke) Hollés, but in view of the 
above considerations and of the constantly non-septate character of the spores 
obtained both by Miss Jamieson and ourselves from certain forms of fruit 
disease, even under cultural conditions, it seems desirable to retain both these 
names. As stated previously, the generic distinctions between Phoma and 
Diplodina seem to have broken down in this group of fungi, and we appear to 
be dealing here with a series of closely-related forms, rather than with clearly- 
defined species. 
