Trillium 85 
At times when this length of pollen tube has been reached, it 
bursts, this always taking place at the end and often with considerable 
force so that the contents is generally forced out through a small pore 
and in a small stream (Plate I, Figure 3). The contents then collects 
as a ragged edged-mass at the end of the small stream of contents 
whose length is controlled by the force of expulsion, which is generally 
sufficient to force out the stream of contents to a length about equal 
to the diameter of the pollen tube (Plate I, Figure 3). When placed 
in distilled water the pollen grains of Trillium nivale frequently ex- 
plode at once and apparently with considerable force, considering the 
size of the grain. This, of course, is due, as is known of some other 
kinds of pollen grains, to a rather sudden increase in the hydrostatic 
pressure of this cell. This, however, occurs in Trillium nivale as a 
rule in an unusually short period of time. Movement of the proto- 
plasm of the pollen tube, as in Plate I, Figures 2 and 3, may often be 
seen. 
The elongated epidermal cells of the stem are often filled with red 
colored sap and, partly due to rapid growth, have unusually thin outer 
walls for cells in such a position (Plate I, Figure 4). The nucleus is 
large in proportion to the size of the cell and several nucleoli are usually 
present. The red cell sap, when present, partly conceals the chlorophyll 
granules. The lateral walls of the epidermis even though very thin are 
provided with shallow pits (Plate I, Figure 4 K), which can just be ob- 
served when magnified 300 times. These pits, which are often seen 
in the walls of internal cells of many plants, are brought out with great 
definiteness when magnified 1,060 times. They are then observed to 
have rounded edges and are rather broad (Plate I, Figure 5 K). 
The cells of the epidermis from the upper side of the leaf of Tril- 
lium nivale are wavy in outline and show no stomata. A slow move- 
ment of the protoplasm can generally be seen under favorable condi- 
tions in the various strands. The nucleus which is sometimes about 
central and sometimes parietal is rather large and shows in many cases 
several nucleoli (Plate I, Figure 6). Pits in the walls, as at H, Plate 
I, Figure 6, are barely discernible when magnified 200 times. The cells 
from the midrib on the upper side of the leaf of Trillium nivale show, 
as would be expected, a decided elongation and reduction in diameter. 
A large nucleus and rather actively moving protoplasm at times are 
generally much in evidence, the latter especially when magnified 450 
times (Plate I, Figure 7). 
The lower epidermis of the leaf of Trillium nivale shows, as usual, 
the presence of stomata. The chlorophyll granules are very few in 
number, but active movement of the protoplasm is often evident. The 
nuclei are rather large, often nearly equalling the diameter of some of 
the cells. The stomata, which are present on the lower surface of the 
leaves exclusively, are generally arranged so that one communicates 
with a respiratory cavity. Some departures from this arrangement are, 
however, present, as when two stomata are over one respiratory cavity 
as is shown in Plate I, Figure 8. The writer has shown this to be the 
case in a former paper.’ In the paper referred to, the history and 
1 Andrews, F. M. Proceedings of the Indiana Academy of Science, 1914, pp. 209-211. 
