
Notes on Self-pollination of the Grape.* 
The grape has small greenish blossoms, which open in a peculiar 
and interesting way, protecting the stigmas from outside pollen 
till they have opportunity to become self-fertilized. The petals 
of the opening flower form a kind of cap which covers the sexual 
organs. When the flower begins to open, the petals break away. 
from their attachment at the base, but remain fastened to each | 
other above and thus keep the stigma and anthers covered. The | 
petals finally curve outward and upward from the base and the 
expansion of the stamens usually lifts and dislodges the cap. 
The calyx in all Vetacew is practically obsolete and plays no part 
in the opening of the flower. In Cissus and Ampelopsis, which 
are nearly related to the grape, the petals open at the top and 
expand in the usual way. 
An opening bud is shown in Fig. 17; @ being a petal just 
detached at the base, and curved outward, disclosing a portion 
of a filament }, and a portion of the outline of the pistil. Fig. 18 
4 

a Fig. peas Opening bud of grape blos- Fig. 18 —Diagramatic illustration of 
. som showing the manner in which grape stamens. 
the cap becomes loosened at the base. - 





4 _ shows the pistil with the cap removed, and illustrates the expin- 
sion of the different forms of stamens. If the flower has short 
filaments, as at a, they become reclined 6 or recurved ¢. If 
the flower has long filaments d they become erect, as at e. | 
~ * A portion of this paper was read atthe Rochester meeting of phe American Association for 
. the Advancement of Science, August, 1892. 
A 
