94 THE JOURNAL OF BOTANY 
n other cases the wo carpels are of ee ene the same size, 
and both bear oe They are completely fused below to form a 
nature is concerned, but that their tee n ithe is anomalous. 
Comparison with related orders, e.g. the Connaracee, confirms this 
opinion. 
Ar the meeting of the Society on 4th February, Mr. a : 
Salmon exhibited two specimens of Epilobium collinum C. C.G 
from Scotland, with a series of H. montanum and E. restr en re 
comparison, = read a note which will appear in this Journal in 
an extended form. Dr. §S. H. Vines, the President, gave an account 
of some a into the physiology of the Yeast-plant (Saecharo- 
myces Cerevisi@). Mr... Salmon gave an account of his “Further 
Researches on the ieniaiiiaion of Parasitism in the Erysiphacea.” 
The oonpanntive inoculation-experiments of 1650 leaves of various 
species. of Bromus, carried out by the author at the Cambridge 
University Botanical Laboratory, have shown that a very high 
degree of specialization has cto reached in the adaptive eee 
of Erysiphe Graminis DC. to the different species of the gen 
Bromus. This spenesten had involved the evolution of a ¢ 
siderable number of ‘‘ biologic forms” of thefungus. The complisatil ae 
ree of these ‘ ha forms’’ with their host-species were 
‘Up 
‘*hordeaceus,”’ B, commutatus. B. racemosus, B. velutinus, B. arvensis, 
B, tectorum, and B. arduennensis. The author pointed out that it 1s 
‘‘ biologic forms,” to show the presence of specific physiological (or 
constitutional) characters in a plant. As a rule, each species of 
Bromus shows physiological characters which hold good for - ex- 
amples of the species obtained from different localities. But there are 
oe to this rule, and the author pointed out that “ biologie 
forms’’ of host-plants exist. Details of experiments were given in 
Which definite proof was obtained of the function of certain species 
of Bromus as ‘‘ bridging species.” In inoculation-experiments s with 
that in the genus Spherotheca—as in Erysiphe—specialization of 
parasitism and ge Lereen of ‘‘ biologic forms” have taken place. 
e experimen Erysiphe Cichoracearum on o major 
Pay the Oidium-stage. From observations made in the field, the 
author has sacettaitinl the constant association of a mycophagous 
Jarva with the Oidium-stage of many species of the Erysiphacee. A 
