New York Agricuururau Exprriment Savion. 397 
itself! There may be other minor factors such as quantity of 
pollen produced, lack of affinity, etc. but this one is sufficient to 
account for all of the phenomena observed both in the field and 
laboratory. . 
These results raise the question in the author’s mind as to 
whether the grape is not now, so far as its phenological characters 
are concerned, in a state of evolution from an older hermaphrodite 
form to forms that are essentially staminate and pistillate. All 
of the staminate flowers, so called, which I have observed have 
small abortive pistils; which also conforms with the observations 
of Engelman.? Others report staminate flowers with no trace of 
pistil remaining. On the other hand the most advanced pistil- 
late forms still retain their stamens although so far as their 
true function is concerned they are apparently abortive. There 
is considerable corroborative evidence that this incomplete evo- 
lution has taken place. The whole path is marked by transi- 
tional forms; thus there are no distinct classes of self-sterile and 
self-fertile grapes but all gradations exist from one extreme to 
the other.2 This blending is quite apparent from an examination 
of pollen from a dozen or two of varieties selected by chance. 
In selecting the varieties which are given in the list in the early 
part of this bulletin extreme types were chosen purposely so that 
any difference which might exist would be most apparent. It 
further appears that pollen from the same variety may vary 
slightly in different years and even the same year in different 
localities.4 These facts seem to show that our grape is in a 
state of very unstable equilibrium, coming from an ancestry of 
diverse sexual types.® 
It might be interesting to consider the probable cause of this 
evolution. It seems reasonable to suppose that there must be 
some advantage which the staminate and pistillate vines have 
1Such plants are well known and are called by botanists pseudo-hermaphrodites. I am 
not aware, however, that any of our cultivated plants have been heretofore recognized as 
belonging to this class. See Natural History of Plants, by Kerner, page 291. 
?Bushberg Catalogue, page 7. (Edition of ’95.) 
3See Bul. No. 157: 424 et seq. 
‘Beach, Bul. No. 157: 424. Bushberg Catalogue, page 8. There is a vine on this station 
which bears both staminate and hermaphrodite flowers. Mr. N. B. White, Norwood, Mass., 
reports that he has a male (?) Rip. X Lab. vine which has fruited twice in the last thirty years, 
_ the pistils evidently varying in strength but being generally too weak to produce fruit. 
5Natural History of Plants, page 300. 


