154 
MEMORANDA. 
Drorcovs FORMS OF VITIS VINIFERA, .L.—On page 42 of the Proceedings 
of the Academy, I offered a few observations tending to show that the idea of 
De Candolle veo adopted by others), that Dioicousism was a peculiar attri- 
bute of the American species of Vitis and Hermaphroditism of the Euro 
2 
wa 
genus, ought to be corrected ; and further, I suggested that the seedless grapes 
of Europe (Currants) were probably pistillate forms. This has produced two 
letters from Dr. George Engelmann, of so much interest that, with his know- 
ledge, I make the following extraets :— : 
“ Tt is a well-known fact that V. vinifera, when running wild, as it occurs in 
different localities on the banks of the Rhine, becomes polygamous; and I 
have specimens of male plants in my herbarium. ‘The berries are small, acerb, 
and dark bluish-black 
“ The same, I have learnt from Prof. Parlatore, of Florence, grows fe the 
near Leghorn, and is as large a plant there as our largest V. 
cordifolia (or viparia),—a hundred feet high, and (stem) six or eight incheei in 
diameter,—and is there yet called * Labrusca’ by the natives,—the ancient 
name used also by Virgil and Pliny, showing the same plant to be wild (native 
or naturalized ?) at their time. This is also said by Professor Parlatore to be 
“The number of seeds does not depend on the fertility of the plant, but on 
the size s the berry; thus our small berries, V. cordifolia (viparia), bear 
_ one or two reds, rarely, if ever, more. 
** The question with me is whether the plant is ever properly dioicous ? I 
have never found female plants. All that I could examine were either male or 
hermaphrodite, though the hermaphrodite may not be absolutely perfect,—that 
is, though the pollen is perfect, it may require the pollen of another (male or 
hormophrodite) plant to fertilize it, 
“ Has any one seen purely female plants ? 
“ Your hypothesis of the fous Currants I cannot share. If notimpreg- 
nated, the fruit be come to nothing; but there are seedless varieties of different 
plants you kno 
In another lint; i in reply to some suggestions of "ine Dr. peeing adds: 
“T was too hasty in saying that a non-fertilized fruit would not ripen. en 
with a fleshy calyx (epigynons) often do, d dva seeds; but of 
grapes I would doubt it. And, moreover, I do not know—and would like 
botanists to look E female flowers are found in Vitis; 1 find only 
complete or male plants,—have never seen a purely female. If no one has, 
will they look out next season ?” 
These extracts confirm my views in reference to the existence of imperfect 
forms of V. vinifera, and they open up an interesting inquiry as to the cause 
of seedless raisins. One of our fellow-mem bers suggests that my hy pothesis, 
that they are pistillate forms, imperfectly developed through lack of fertiliza- 
