285 
garden well-removed from the other locality. The eelworm had 
attacked and caused the deaths of the Antirrhinum plants and 
the usual galls were present in the roots. There was no softening 
of the stem such as would be induced by the Fusarium wilt, and 
although mycelium was found in the affected soil and on the 
small lateral roots behind or in front of the Heterodera galls and 
shown to be in both cases that of the Fusarium, there were no 
hyphae in the tissues of the plants except in the galls and the 
smaller roots mentioned. The external mycelium was white and 
accompanied by microconidia on the small roots, and it passed 
from one root to another in strands strong enough to hold 
together particles of soil. When grown in culture it was typical 
of former growths. In one case, the soil mycelium gave rise 
in culture to two fungi, the Fusarium and Sclerotium Rolfsii, Sacc., 
the latter of which had been found associated externally with 
the carnation wilt in 1919,* but no S. Rolfsii was derived from any 
tissue-fragment culture. The presence of hyphae in the galls was 
demonstrated by sections, and their connection with the Fusarium 
was shown by inoculating the media previously used and also 
potato-dextrose agar with fragments of galls teased out in sterile 
distilled water. The Fusarium was obtained also from fragments 
of roots cut from nzar the galls. In the case, therefore, of the 
Antirrhinum plants, it was concluded that the Fusarium was 
introduced directly or indirectly into the galls and thus indirectly 
into the root tissues by Heterodera and that there was no evidence 
of its being truly parasitic on the plants. Adjacent plants were 
not attacked either by fungus or nematode. The case of the 
carnations was somewhat different, for, while they showed all 
the symptoms of Fusarium attack, there were no galls on the 
roots. The eelworms were confined to the crown-rot area of the 
stem and to the collapsed tissues of the smaller roots. Carnations 
which had not been attacked by the Fusarium were not attacked 
by the eelworms. Nematode root-galls frequently contain a 
species of fungus, and it was not surprising to find in the fungus 
a known soil-dweller and one capable of being destructively or 
weakly parasitic. The relationship between Heterodera and the 
Fusarium was in all probability an accidental one arising solely 
from the proximity of the one organism to the other, and leading, 
in the case of the Antirrhinum, to a degree of parasitism so feeble 
that it was only just removed from saprophytism. The case of 
the carnations, again, revealed the AHeterodera as a mere 
agent in the destruction originated by the Fusarium. At a 
later date, galls formed on the roots of Thunbergia erecta, J. Anders. 
by Heterodera radicicola were examined for the presence of the 
Fusarium with entirely negative results. 
IDENTITY OF THE FUSARIUM. 
During the progress of the work recorded in the foregoing 
pages, the writer had been struck with resemblances, details of 
* loc. cit., p. 327. 
