xiii, c, 6 Brown and Trelease : Shrinkage and Elongation 355 



Table I. — Measurements of shoots of plant 1 of Cestrum noctumum at 

 various hours during the day and night. 



Time. 



p. m. 

 12.30-. 

 1.30.- 

 2.30... 

 4. 00.. 

 6.00.-. 

 8.30... 



a. m. 



7.00... 



8.00... 



9.00---. 

 10.00. ... 

 11.00.... 

 12 noon. 



p. m. 



1.00— _ 



2.00-... 



3.00.... 



4.00.... 



6.00.... 



6.00.... 



8.00.__. 



Tem- 

 pera- 

 ture. 



Evapo- 

 ration 



per 

 hour. 



Illumination. 



1.32 

 1.38 

 1.20 

 0.84 

 0.90 

 0.30 



0.18 

 0.58 



1.34 

 1.63 

 1.63 

 1.44 



2.30 

 2.40 

 2.11 

 2.21 

 2.21 

 1.34 

 0.72 



Shade 



do 



do 



do 



Dusk. 

 Dark .. 



Sun. 



do 



do 



do 



Diffused light 



Shade 



do 



do.. 



....do 



do..._ 



Dusk 



Dark 



Measurements of shoots. 



Shoot 

 1. 



cm. 

 9.40 

 9.60 

 9.60 

 9.50 

 9.66 

 9.75 



10.25 

 10.20 



10.10 

 10.00 

 10.00 

 10.06 



10.05 

 10.10 

 10.10 

 10.10 

 10.10 

 10.15 

 10.20 



Shoot 

 2. 



cm. 

 7.60 

 7.65 

 7.65 

 7.65 

 7.75 

 7.85 



8.26 

 8.25 



8.10 

 8.10 

 8.10 

 8.16 



8.16 

 8.16 

 8.20 

 8.20 

 8.25 

 8.25 

 8.25 



Shoot 

 3. 



Shoot 

 4. 



cm. 



cm. 



12.50 



7.60 



12.60 



7.65 



12.60 



7.65 



12.65 



7.70 



12.70 



7.75 



12.85 



7.80 



13.30 



8.25 



13.30 



8.30 



13.16 



8.20 



13.05 



8.15 



13.10 



8.15 



13.10 



8.20 



13.15 



8.20 



13.20 



8.20 



13.20 



8.25 



13.25 



8.25 



13.25 



8.25 



13.25 



8.30 



13.30 



8.30 



Condition of shoots. 



Much wilted. 



Do. 

 Less wilted. 

 Slightly wilted. 

 Straight. 

 Curved upward. 



Do. 

 Slightly curved 



downward. 

 Very visibly wilted. 

 Much wilted. 



Do. 



Do. 



Less wilted. 

 Slightly wilted. 



Do. 

 Very slightly wilted. 



Do. 

 Straight. 

 Curved upward. 



noon, when the first measurement was made, the shoots were very 

 much wilted, as they were also at the time of the second measure- 

 ment. Following- this they became less wilted and were straight 

 by 6 o'clock, and at 8.30 in the evening they were curved upward. 

 This whole period was one during which the shoots were ap- 

 parently recovering from wilting, and in doing so they showed 

 an elongation amounting in the different cases to between 2 

 and 3.5 millimeters. At 8.30 in the evening the shoots were 

 curved upward and apparently had completely recovered from 

 wilting. Between this hour and 7 o'clock in the morning, when 

 still turned upward and apparently very turgid, they showed 

 an elongation varying in the different cases between 4 and 5 

 millimeters. By 8 o'clock, after having been exposed for a 

 short time to the sun, one of them had decreased in length 0.5 

 millimeter and another had elongated 0.5 millimeter, while the 

 other two had shown no change. The shoots at this time were 

 curved downward slightly. By 9 o'clock all of them were vis- 

 ibly wilted, and all had shortened either 1 or 1.5 millimeters. 

 At 10 o'clock they were very much wilted, and all except one 



