115 
van Hall. The complex nature of the St. John’s disease 
originally thought to be caused by one and the same 
parasite, is thereby established. In addition to the 
above-mentioned species found in peas a third is added, 
namely F. avenaceum (Fr.) Sacc. This species was re- 
peatedly isolated from diseased peas. Appel and Wolle n- 
weber express the opinion that probably more species 
belonging to the genus Fusarium are to be found on 
this host, just as in the case of the potato, which is 
inhabited by a great variety of different Fusaria. Since 
then additional species infecting peas have been added 
by Wollen Weber (4), for instance F. reclolens Wr., a vas- 
cular parasite causing a wilt and foot-disease in peas, 
and finally, F. Martii App. et Wr., which is perhaps 
merely a saprophyte. 
As will be seen, the old conception of the cause 
and nature of St. John’s disease cannot be upheld. In 
attempting to ascertain the proper cause of wilt in peas 
it becomes necessary to isolate and cultivate the fungus. 
The direct effects of the parasitism of the different 
species on the host are probably not the same in all 
cases, but closer inquiry is necessary before any diffe- 
rentiation of the various species can be made on the 
basis of the different effects on the host induced by the 
parasite. — The short and vague diagnosis given by van 
Hall for F. vasinfectum var. Pisi is too unsatisfactory to 
allow of an identification of this fungus with those publis- 
hed later. There are, however, grounds for the belief 
that van Hall’s species is identical with that described 
by Wollenweber under the name of F. reclolens l . 
2. The present disease; its cause and symptoms. 
In the early part of September, 1918, I had the 
opportunity of examining an extensive field of garden- 
1 I am greatly indebted to Dr. H. W. Wollenweber for infor- 
mation on this point, as well as for his kindness in checking my deter- 
minations of certain Fusaria. 
