THE STARCH OF EVERGREEN LEAVES 337 
BEHAVIOR OF STOMATA IN WINTER. 
The continual exchange of gases between the intercellular 
Spaces of the leaf and the surrounding atmosphere is necessary 
_ forphotosynthesis, and this interchange is mainly through the 
stomata. Therefore, if the stomata be tightly closed, the 
photosynthetic process may practically be stopped in spite of 
favorable temperature and illumination. Hence it would not 
te superfluous to note, the opening and closing of the stomata of 
‘vergreen leaves in winter, as observed in Tokyo. 
Stahl showed, in accordance with Schwendener™ and Leit- 
gb that the stomata of evergreen leaves are closed during the 
“ater, and also that the closed stomata of Taxus and Mahonia 
pen after being kept for a week in a warm room, while those of 
Suxus and Hedera open after ten days. A similar fact was” 
observed by Lidforss (/. c.) in the case of Saxifraga, Iris, and 
Utium, oe 
Darwin 
leaves in win 
verified the closure of the stomata of evergreen . 
ter with his newly devised horn hygroscope. But | a 
ef mentions some exceptional cases where they were found clearly : 
pen on January 20 (temperature 12°5) in the warm winter of 
Se in Prunus Laurocerasus, P. Lusitanica, Hedera Helix, 
pela Bursa-pastoris, and Chetranthus Cheiri; while Buzus sem- 
and Mex Aguifolium had closed stomata. ee: 
testing the opening of stomata I have adopte 1 Stahl’s 
test. The leaves, after removal, were brought immedi 
4 the laboratory, the temperature of which varie a 
_. / +and covered with dried light-blue cobalt paper,” pro- 
~~ Nboth sides from the moisture of the air by two glass plates. 
uy coe Einige Versuche ueber Transpiration und Assimilation. rp ee 
WENDENER, S 
Beri, >” Ueber Bau und Mechanik der Spaltéffnungen. Monatsb- 
Berlin, 833. i881, oe 
CkR, H., Beitra >hysiologie der Spaltéfinungsapparate. Mittheil. 
Graz 1 1856, 8¢ zur Physiologie der Spaltéffnung: — oe 
, a F., Observations on stomata. Phil. Trans. Roy. Soc. London Bot- 
oe by Soaking the filter paper in 2-4 per cent. cobalt chloride Sane - 
