202 Macfarlane—Current Problems 
with the possibilities of protoplasmic fusions and transfusions, 
as well as nutritive adaptability. 
No fact impressed me more in the study of Cytzsus Adami 
as a probable graft hybrid, than the remarkable differences in 
the epidermal nuclei of the composite organism. While those 
of the arborescent C. Laburnum portion are relatively small 
and rich in chromatin material, those of the smaller parent 
portion, C. purpureus and of the hybrid, are large and much 
less refractive in their nuclei. 
At the present day the complaint is sometimes made that 
plant taxonomy is being neglected for the cultivation of plant 
morphology and physiology. In one sensethe complaint is a 
just one. But is it not true that we are only beginning to 
realize what plant individuals, plant varieties and plant species 
are, as we compare cell with cell, and tissue mass with tissue 
mass? That this is correct is evidenced by the rapidly grow- 
ing popularity of that most recent departure which I will now 
shortly touch on, namely: 
(ce) Ecotocicat CyroLtocy.—That cells, and therefore plant 
parts, can be molded by their surroundings, we accept as 
proved by experiment. Shortly, it may be said that environ- 
mental stimuli act on every living plant cell, while the cell 
reacts temporarily or permanently to the stimulus. This fun- 
damental law of plant life is only beginning to be realized in 
all its fullness. But while the general relationship of plants 
to their surroundings in respect of form, consistence, size and 
color should be noted, it soon becomes evident that these data 
have to be corrected and supplemented by a study of indi- 
vidual cells. It is a significant omen of present day progress 
that Schimper’s splendid work on plant distribution recognizes 
continually not merely those agents which we class as the 
environmental stimulants, but equally the cytological changes 
which such stimulants produce. So exact is this line of 
inquiry becoming that we may soon be able to speak not only 
