Maefarlane, The Sensitive Movemeuts of some Flowering Plants. 141 



September 13th. The day was heavy and cloudy tili 

 about 1 p. m. Thereafter bright sunshine alternated at rather 

 long intervals with cloud-shade. The leaflets of every plant re- 

 mained open in the forenoon, but by 1:45 those of 4 were in- 

 flexed 10 — 15". It had recovered by 4:20, and by that time 

 plant 1 showed slight nyctitropic movement. For the remainder 

 of the day observations eould not be made. 



September 14 th. The sky was dnll and leaden tili 12 

 noon. From then tili 1 : 30 there was bright sunshine, but no 

 observations could be made tili 3 : 30 when every plant showed 

 expanded leaflets. At 3 : 55 the leaflets of plant 1 began to inflect ; 

 at 4: 15 a flu on plant 2 had slightly moved, others were still 

 flat ; at 4 : 30 those of plant 1 had moved through an angle of 

 65°, those of plant 2 through 40°. Plant 3 had just started at 

 4 : 30, and a few leaflets of the exposed plants had also moved, 

 though most were flat. At 5 : 10 the leaflets of 1 were closed, 

 those of 2 were fully two thirds closed, those of 3 were fully one- 

 third closed, and the leaflets of plant 4 were still expanded. At 

 6 p. m. plants 1 and 2, also those in the open were closed, plant 

 3 had almost closed, but the leaflets of 4 were flat except for a 

 few at the ends of the younger leaves which had slightly inflexed. 

 At 6 : 30 the leaflets of 4 had all moved through an angle of at 

 least 25°, some considerably more. At 8 : 30 when next examined, 

 all had closed. 



September 15 th. The day was bright and warm. As on 

 previous days, the leaflets of plant 1 at 7 : 30 were decidedly, 

 and those of 2 slightly reflexed. Plants 3 and 4 had flat leaflets. 

 At 9 : 30 the sun temperature was 34° C, and the shade temperature 

 28.5° C. The screen temperature was 31.5—34° C. Plant 1 

 had reflexed leaflets, plant 2 Hat or very slightly reflexed, plant 

 3 from flat to inflexed through 10*> and plant 4 inflexed through 

 about 30°, being intermediate in position between the plants on 

 the lawn and that against white back-ground which indicated 

 40°. At 11 : 30 plant 1 showed slight inflexion of its leaflets. 

 Want of moisture would not account for this as all had been 

 carefully watered on the previous evening. As the screen tem- 

 perature was 36.5° C, it may be that a slight heat Stimulus had 

 taken effect here. The leaflets of plant 2 were flat ; those of 3 

 were inflexed 10 — 15° on the older leaves, and 20 — 25° on the 

 younger ; those of plant 50 — 55° on the younger leaves. 



At 2 : 30 the sun temperature was 36.5° C and shade 

 30.5° C. The conditionsremained the same as above, except that a 

 moderate re-expansion had taken place in the leaflets of plant 3. 

 By 4 : 30 plant 4 had re-expanded through an angle of 25°, and 

 by 5 : 15 the leaflets were flat. At 4 : 10 plant 1 had begun to 

 close, at 4:40 plant 2, at 5 : 15 plant 3, and at 5:45 plant 4. 

 By this time 1 and 2 were closed, and 3 was fully two-thirds 

 closed. At 6 : 30 the leaflets of 4 were nearly all closed. 



