STOMATA OF TRILLIUM NIVALE. 
F. M. ANDREWS. 
Giimbel! was the first to make known the presence of twin stomata. 
Since that time Pfitzer*? and others have shown the presence of stomata in 
groups of two or more on the leaves of various plants. In Sawrifraga sar- 
mentosa stomata are aranrged “in circular groups’* in considerable num- 
ber. In various species of Begonias, as De Bary states* in Begonia mani- 
cata, B. spathulata, B. Dregei and B. heracleifolia two or more stomata 
are arranged over one respiratory cavity. 
This occasional grouping of the stomata in certain plants is even more 
strikingly shown in Trilliwm nivale. The stomata are often found on the 
leaves in pairs over a common respiratory cavity, but frequently in num- 
bers up to ten or more. In opening and closing they act just as a single 
stoma does. 
The presence of more than one stoma over a common respiratory 
cavity is also shown on the sepals and petals. Figure 1 shows part of a 
sepal of Trilliwa nivale in which the stomata are in pairs in one case and 
in threes in another case over a common respiratory cavity. These arise 
from the successive division of a common mother cell. The stomata on 
the sepals and petals are frequently lateral or diagonal as regards one 
another, but in every case their origin from one mother cell is the same. 
The arrangement in groups of as many as ten or more over one respiratory 
cayity on the sepals or petals is also met with. 
Figure 2 shows a case, taken from the outside of a sepal, where only 
one guard cell, A, is fully formed. There is only a remnant of a second 
guard cell, B. The same thing has also been observed on the inside of the 
petal. 
\Giimbel. Jahr. fiir wiss. Bot. Bd. 7, p. 551. 
*Pfitzer, E. Jahr fiir wiss. Bot. Bd. 7, pp. 532-560. 
?Treviranus. Verm. Schriften, IV. 30. Quoted from DeBary, A. Comparative Anatomy of 
Phanerogams and Ferns. 1884 p. 47. 
‘Vivani. Quoted from DeBary as above. 
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