THE STARCH OF EVERGREEN LEAVES 
January and the beginning of February, increasing again from. ae 
the end of February. As in the mesophyll, the amount of oo 
Sarchin the guard-cells becomes less or even entirely disappears 
- in winter, Among the plants examined, less than half were 
found to have the stomata free from starch during midwinter. — 
The increase or reappearance of stomatic starch was. found to 
occur later than that in the mesophyll. ae 
Itshould be noticed here that the starch contents of ever- 
‘fren leaves are generally greater in April than in August or 
mber. This fact was already noticed by Mer,® who 
femarked that some unknown internal causes may have an © 
influence on the formation and accumulation of starch besides 
the known factors. 
a Lidforss (2. ¢.) noticed that the leaves are quite free from 
alcium oxalate crystals in winter, and he believes that this is 
rable to the economy of plant life, since otherwise they 
ld afford centers for ice-formation within the cells. Although - 
: t decrease appreciably in winter. oe 
des the plants already mentioned, I have examined some 
fous plants in the winter time. The results are 
Date Pal. — 
ths ee December 25 I = 
ne January 18 se ahs 
February 12 0 - 
Sieve: uary 18 ° . 
Bt rene sce. February 13 . ae 
oo uary 16 o : 
SN ele eee January 18 I cme 
ag Pastoris. . ee January 18 2-3 — 
Scolymus ae January 18 Ot bse 
quelques causes intermes sur la présence . 
8. 1891. — 
Rend. rr2:248. 1891 
Compt. 
