1921] CRIBBS—TILIA AMERICANA 291 
rapidly in the morning, beginning at dawn or shortly after. This 
early rise was attributed by Lioyp (7) to the opening of the 
2 transpiration 
—— ee ee semperarkuve 
elles eee ck eo 
wee Yelatwe humidity 
ae 
Ba ho Ali 
ss ia 
20 Sa 
2 af :. 
. L Ee . 
90 { ea: ca Sieg ta ow 
- io PRB ee OS Jj 8 1] 
oe oe Se nie Srmatolasie cas 
peer ct o 
tho —“"Tlo0 #]00qloo tobe iloo ifootloo aloo sfoo ‘loo 3100 = 6f00 Moo 
Fic. Data taken at station J on June 7, showing appr de mene concurrence of 
maxima in Wife curves; legend applies to afl figures except fig. 
23 
ar 
25 
23 
pa ba 
ing 
7 
ue 
Loo oo s FOO~SCOO:SC«dODCOssC‘sC 
200 
2.—Record of data for station K, take 
Fic n Washington Park, Chicano, 
August 163 note gradual rise and decline of sed cares Toei 
stomata under the influence of light. That there is a sudden 
Opening at this time has been verified by direct examination 
recently by Sayre (8). In working on Nicotiana and Verbascum 
