1904 ] 
DARWIN: MOVEMENTS OF STOMATA 97 
EXPERIMENT 15, fig. 9. February 21, 1899. TROPAEOLUM. 
A. M, 
9:30-10:6 Zero line drawn, nothing on either bulb. 
10:6 
10:6 
<— R.COOL. 
Attached leaf on bulb R, withered leaf on B. 
<a 
12-13°, Psy. 77-78%. A gradual opening of stomata till 
1x2 
Plant moved to dry greenhouse (T. at noon 25°, Psy. 40%). 
A sudden R-cool move, owing to increased evaporation but 
there was no sign of a permanent R-warm move (which would 
have indicated a closure of the stomata) until 2:15, although 
the air remained very dry, ¢. g.,at3P.M. Psy. 35%, T. 24.1", 
and at 5:2 P. M. the psychrometer still gave 40% and the 
temperature was 23.5°. The rise of the curve (R-warm 
move) was probably due to a genuine withering of the 
attached leaf, though the horn hygroscope did not indicate 
any closure even at 3 P. M.; at 5:40 the temperature curve 
shows complete closure, and this is confirmed by a horn 
reading at 5:50. 
Be I say 
Coo 
Se ee er Sees Gael Ge a ee i— 
ee ee ee eS ee Gee Geel 4 
= 
ae Be ee ee ee ee ee 
F ES Se oe eee Ge ee 
Re ee eee ee ee oar ae oe Se ee ee 
a es ee ee ee Se Oe ee 
= Bk ae eee ee 
x eee eee 
=e SS SS os Gee ee Gs ee ee es ee an cn in Oe 
= | EVRS AS mr 
“A 
Pa 1 san Rs a Rae MS 
BOS hh 
So 
rs] Mt 
= Re ae ee ee ons Gee Gn Ge ee 
| 2S 2S ee ee ee ee con Gee Gael Ge ee ee 
a Be Se ee eS ee ee ae ee eee Ge es eee 
} ‘v 2 SS oo ee ee ee ee ee ee 
} Pa De ee ee ee ane ee Ge el ee 
LA 
a ee ee eee ae ae eee 
Re ee ee ee eee ee ne ee es ee 
| PEPPER 
l pe Ee 
sod a t's] tt 
a toa ” Pe 
~ ~~ or ws = 
_ 
Fic. 10.—See Experiment 17 B, p. 98. 
