1905] SHOEMAKER—HAMAMELIS VIRGINIANA 257 
but as winter approaches the base of the funiculus becomes glandular. 
The epidermal cells enlarge, the walls thicken, and the contents 
become vacuolated. In the spring this process is carried still farther, 
and as the ovule occupies more and more of the cavity of the ovary, 
these cells secrete a mucus which fills the small remaining cavity 
around the base of the funiculus (jig. 10). 
THE DESCENT OF THE POLLEN TUBE. 
The pollen grains begin growth very shortly after falling on the 
stigma, and the growth is at first comparatively rapid. Its course 
is readily traced in the conducting tissue of the style, which is greatly 
disorganized by the growth of the large number of tubes usually 
present. The course is between the cells rather than through them. 
By the time that winter sets in the living part of one or more tubes is 
to be found in the neighborhood of the base of the funiculus (fig. 
11). There are usually several living tubes at varying heights in 
the style at this time ( figs. 17 and 18), and evidence of many more 
which have. been stranded above. The unprotected tip of the style 
is dead and withered, while that part which is clothed with hairs is 
alive. It is in this protected part of the carpels that the pollen tubes 
hibernate. Soon after pollination the flower head twists on its stalk 
so as to invert the blossoms. The inverted calyx then very effectually 
Protects the carpels from rain, sleet, and snow. 
The pollen tubes found at this time are usually of greater diameter 
than at the beginning of growth. Tubes grown in sugar-gelatin 
solutions are 5 to 8 w in diameter, and those which sprout on the 
stigma are at first about the same size; but those found during the 
resting stage are 12 to 15 # in cross-section, and the wall is thicker 
than. at first (fig. 14). The nuclei found did not exceed two in any 
tube. 
When growth is renewed in the spring, the area of conducting 
tissue in the funiculus being increased, the pollen tube is soon seen 
In the cavity of the ovary. More than one tube may reach the ovary. 
At first the ovule is by no means ready for fertilization, and the 
integuments have not yet closed up the micropyle (fig. 21). The 
tubes do not appear at this time to have any definite direction of 
Stowth, but grow down beside the ovule or into the.wide open 
