MISS S. LONGMAN ON THE DRY-ROT OF POTATOES, 123 
by any external condition such as the medium in whieh the fungus grows, 
unless, indeed, they are due to chemical changes in the medium caused by 
the fungus itself. | 
This conclusion is in disagreement with that of Smith and Swingle (204), who 
find that “the form, colour, and habits of growth of this fungus depend much 
on the medium in which it is grown." 
The colours found by these authors and by myself were in most cases the зато, 
but whereas I have not seen the lilae, violet, and purple shades that they 
deseribe, they do not get the shades of light and dark blue commonly found 
at Reading. 
Smith and Swingle obtained the purple shades in Fusarium growing on the 
following media :— 
Boiled rice, lilac (also pink and white). Silicate jelly, lilac (also pink, rose, 
and salmon). Boiled corn, purple (also pink and white). Boiled tapioca, 
deep violet (also white). "Whereas I have obtained white, buff, pink, and light 
and dark blue, all in one and the same medium, viz. potato. 
Fusarium Solani has been placed among the lowest of the Fungi imperfecti, 
in the Hyphomycetes. It would appear from the pycnidial nature of the 
pustule that it should rather be placed in the highest group, viz. the 
Sphreropsidales (Lindau, ?00). 
By reason of the pycnidia, the fleshy and waxy stroma and the hyaline 
spores, it falls into the Nectrioidaceæ, sub-division Zythieæ ; and by its 
spindle-shaped spores and general characteristics of stroma (being brightly 
coloured, etc.) it may be placed in Aschersonia. 
It is not unlikely that in an appropriate medium F. Solani might be induced 
to form ascus-fruits, and so show itself to be a typical ascomycete. In this 
connection it may be noted that Massee (704) claims to have observed typical 
ascus-fruits succeeding the conidial stage. As this is a matter of some 
importance, a brief account of Massee’s statements may be given. 
This author finds that in its first stage F. Solani, or, as he prefers to 
name it, Nectria Solani (Pers.), forms spores of the Monosporium type. He 
may have regarded as ** Monosporium” spores the young, aseptate, but 
undoubted Fusarium spores which it has been shown can be connected 
up by transition forms with the typical Fusarium spores. In any case по 
Monosporium stage was found on the pure cultures of the fungus grown at 
Reading. 
The second stage described by Massee, in which the fungus changes from 
white to pink, and the typical Fusarium spores are produced, exactly corre- 
sponds to that described in the foregoing pages. Massee further states that 
the typical spores yield a third type of spore produced in ball-like masses of 
gelatine (the Cephalosporium stage). In no case amongst the many germina- 
tions of spores watched in the course of this research, was this Cephalosporium 
к 2 
