256 BOTANICAL GAZETTE [APRIL 
than two nuclei were ever found in a tube. The tubes showed a 
marked tendency toward the formation of cellulose plugs (jig. 12). 
It rarely occurred that part of the contents of the tube was in this way 
shut off, as the spaces walled off by plugs were mostly empty. 
In the course of about three days’ growth the pollen tube frequently 
‘“encysted” (fig. 35), that is a spherical swelling developed at the tip 
or near the tip of the tube into which nearly all the contents of the 
tube were withdrawn, including one or both nuclei. A wall was then 
formed completely closing off the swelling, which was often as large 
as the original grain. I have not determined the exact conditions 
which called forth this action, neither have I found such things in the 
style in normally grown pollen tubes. Miss BENSON (4) reports a case 
of somewhat similar character as occurring in Carpinus, though the 
spherical character and the separating wall were not nearly so pro- 
nounced. She suggests that this may be of use in the short resting 
period of this form, but was not able to find such appearances in the 
style. 
The pollen showed ability to sprout at room temperature whenever 
the flowers opened. A collection made in Ohio early in January; 
after the unopened buds had endured a week of very cold weather, 
~when the temperature had been as cold as —15° F., sprouted ina 
seemingly normal way, though not so vigorously as earlier. I am 
inclined to think, however, that pollen shed so late never functions. 
CONDUCTIVE TISSUE OF THE STYLE AND OVARY. 
By the folding of the carpels each style has a groove fo 
which leads from the stigma to the ovary. It is open at the top, and 
where its sides are slightly separated and its inner surface thus 
exposed, it bears the loosely arranged papillose cells of the stigma. 
The epidermis of the groove and two subepidermal layers continue 
this stigmatic tissue down to the base of the funiculus, the strand 0 
conducting cells getting gradually deeper and deeper in the tissue 
of the style. The cell walls of the strand are thickened, partly 
ized, and the contents of the cells are dense. Fig. 13 shows its appea 
-ance and position about midway in the height of the style, ae 
course in longitudinal section is shown in fig. 18. When the omg 
first opens, the epidermis of the funiculus is not yet differentiate” 
rmed, 
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