STOMATA AND THE SPECTRUM. 113 



Experiment 213.— Verbena ciliata, April 24, 1906. Twig remaining attached to plant 

 arranged under double-walled bell-jar holding ammoniated copper solution, modified 

 by gentian violet. Spectrum shows blue and violet. Set up at 4 h 3o m a. m.; irrigated 

 with water to prevent overheating. 



4 h 30 m a. m. ; temperature 56°F. ; control: Starch abundant in guard-cells; no oil; minute 

 granules in chlorenchyma (chloral hydrate-iodine); o to 3 micra (plate 11, fig. 1). 



6 h 30 m a. m., control: Oil drops begin to be formed and appear large and abundant at 

 9 a. m; starch reduced in amount, as evidenced by the distinctly granular appearance of 

 the plastids when iodine is applied. 



nh30 m a. m.: Experiment concluded; maximum temperature during experiment, 79°F. 



Control: Starch in quite small quantities in guard-cells; abundant in chlorenchyma; 

 oil drops large; 2 to 8 micra (plate n, fig. 3). 



Experimental part: No starch in chlorenchyma; reduced amount in the guard-cells; 

 2 to 6 micra; oil absent. In some guard-cells the amount of starch is almost if not quite 

 as great at 4 h 30 m a. m., but in others it is absent or nearly so. In an average one the plastids 

 are lakey and evidently granular; o to 3 micra, o to 5 micra (plate 11, fig. 2). 



Experiment 215.— Verbena ciliata, April 24, 1906. Conditions as in experiment 213, but 

 begun at n h 30 m a. m., and continued till 6 p. m. 



nh30 m a. m., control: Starch present in guard-cells, but in reduced amount, as indicated 

 by the weak reaction; abundant in some stomata; starch in chlorenchyma abundant; 

 oil present in guard-cells; 2 to 9 micra (plate 11, fig. 4). 



6 h 30 m p. m., control: Starch present in guard-cells in much greater quantity than at 

 n h 30 m a. m.; an increased quantity of starch in chlorenchyma over that at n h 30 m a. m. ; 

 no oil present ; o to 2 micra. 



Experimental part: Plastids densely-staining, indicating an increased amount over the 

 normal at n h 30 m a. m. ; no oil; 1 to 6 micra; a small amount of starch in the chlorenchyma, 

 certainly less than at n h 30 m a. m. (plate 11, fig. 5). 



Allowed to remain under bell-jar all night and experiment continued on 

 April 25 as experiment 217, on the preceding page. 



Experiment 219.— Blue bell-jar set over twigs attached to plants at 6 a. m., April 27, to 

 be allowed to remain thus for several days. Irrigated to keep cool. Maximum and 

 minimum thermometer within. 



April 30, 1906, 6 a. m., o to 2 (3) micra; oil drops present but quite small, i. e., normal 

 for this time of the morning; starch meager or absent in guard-cells, but variable in amount, 

 sometimes plentiful, i. e., in very occasional and for the most part young stomata; no 

 starch in chlorenchyma. These results are based on four separate examinations, the last 

 two examinations with KI + I under oil immersion 1/16 and oc. 3. Occasionally a young 

 stoma having one guard-cell with abundant starch and the other with none. Maximum 

 temperature for period, 86° F. 



April 30, 11 a. m., control: Guard-eell starch rather meager but evenly distributed in all 

 the stomata; starch in chlorenchyma plentiful. 



Experimental part (two samples): Starch entirely absent from both guard-cells and 

 chlorenchyma, not a trace being visible ; 2 to 8 micra. 



May 3, 6 a. m.: Oil drops as on April 30 at the same hour; no evidence of starch in 

 chlorenchyma or guard-cells; o to 2 micra. 



11^30™ a. m.: Maximum temperature for period, ioo° F. 



