104 
edge of these curious bodies, and Kiitzing’s observations appear 
to have been overlooked or ignored by subsequent writers on the 
genus.” 
The subject ‘Seed sterility in plants that reproduce vegeta- 
tively’’ was presented by Dr. A. B. Stout. The principal views 
as to the cause of such sterility were briefly presented and dis- 
cussed and a report was made of some original research bearing 
on the phenomena. 
Seed sterility has long been recognized as frequent and often 
complete for numerous species, both wild and cultivated, which 
are freely and naturally propagated by such vegetative organs 
as roots, tubers, bulbs or rhizomes. The view has very generally 
prevailed that in such cases the vegetative organs prevent the 
development of seeds by diverting and utilizing the food supply 
that is available. The vegetative organs, it is thought, obtain 
food at the expense of the structures of seed reproduction; an 
assumed relationship which has been called ‘‘compensation of 
growth” by Darwin and “quantitative correlation’? by Goebel. 
However, present day knowledge of-seed sterility in plants that 
reproduce by seeds, or like the apple are propagated vegetatively 
by artificial grafting, shows that in many species fertility and 
sterility are relative and are to be ascribed to some element of 
physiological relation operating between the sex organs them- 
selves. In such cases plants that are seed sterile to self-pol- 
lination are highly productive of seed in certain cross-relations. 
Also sister plants of identical vegetative habit grown under 
same conditions may be highly self-fertile. In order words, the 
fertility is relative. 
Evidence is increasing to the effect that seed-fertility in 
plants which propagate vegetatively may be relative. Such ex- 
perimental evidence consists in finding self-fertile plants along 
with self-sterile plants, or in finding that the “‘seed-sterile”’ 
plants will produce seed when properly crossed. In plants 
widely propagated vegetatively it is necessary to obtain a stock 
from a different seed source if one is to test most adequately 
intra-specific fertility. 
Experimental studies bearing on this question have been under 
