THERMONASTIC PHENOMENA 309 



inner half of the perianth ; hence the inner half of the 

 organ is i*elatively the more excitable. 



NEGATIVE THERMONASTIC RESPONSE. 



Response of Nymphaea : Experiment 115. — Many of the 

 Indian Nyynphoeaceoe have their sepals and petals closed 



Fig. 110. — The Thermonastic Kecorder. T, metallic thermorueter attached to 

 the short arm of the upper lever ; the specimen of Nymphcea, N, has one of its 

 perianth leaves attached to the short arm of the second lever by a thread. C' 

 clock work for oscillation of the plate. 



(luring the day, and open at night. I find that the 

 perianth leaves of this flower are markedly sensitive to 



