Some Tomato Diseases. F. T. Brooks and G. O. Searle. 195 
30m X 5p to 8p, and of K 2 from 14p to 30p x 5p to 75 p, 
20 measurements being taken in each case. 
Mention has already been made that form K 2 produced 
typical acervuli on one artificial medium, so that it seems 
probable that these two forms can also be provisionally in- 
cluded under the species Colletotrichum phomoides. 
Sertes 5. 
Series 5 consists only of form N which was a typical species 
of Fusarium. 
On Dox’s agar, the colour of the spores in mass was orange 
salmon. The spores were crescent-shaped with pointed ends, 
2—4 times septate, 3-4 x 24-36. When fully mature, one 
cell of the spore was often thick-walled and apparently func- 
tioned as a resting spore. Two species of Fusarium are recorded 
by Saccardo(z3) as occurring on tomato fruits, F. aurantiacum 
Link, and F. oxysporum Schlecht. var. Lycopersict Sacc., but 
in the absence of comparative cultures, it is impossible to 
identify the species. It is probable that many species of this 
genus would cause a rot of tomato fruits if inserted in them 
through wounds, and in fact a pure culture of Fusarium 
caeruleum obtained from potatoes, produced a soft rot. 
GENERAL CONSIDERATIONS. 
It would appear from this review of a number of forms of 
fungi parasitic on the tomato fruit that the whole question of 
the taxonomy of difficult genera like Phoma, Ascochyta, Diplo- 
dina, Colletotrichum and Gloeosporium is one requiring consider- 
able attention from systematists. At present the species in 
these genera are almost numberless and seem to be added to 
on very slender grounds and without much regard to the true 
relationships between them, which can only be determined by 
careful cultural work. To add new species indiscriminately on 
the grounds of host relationship, or on a variation in some small 
morphological detail, which if studied in cultural form will 
often turn out to be within the “experimental error” or ordinary 
range of variability, is much to be deplored and adds largely 
to the difficulties of later investigators. In the forms here in- 
vestigated, this variability was found to be very marked, es- 
pecially in such morphological details as septation of spores, 
a character often looked upon as specific and one in which some 
systematists beg the question by adding such phrases as “ be- 
coming septate later”’ or “the septation is tardy in appearing.”’ 
