SECT. II 



PHYSIOLOGY 



32£ 



of carpellary leaves may be seen in the flowers oiMimulus, StroMlanthes {Goldfussia), 

 Jfartynia, Turcnia, and other plants. The two lobes of the styles of these flowers fold 

 together when irritated. The stigmas of Mimulus and Turenia open again shortly 

 unless active pollen has been deposited, when they remain in the closed condition. 



a 



A H 



Pio. 241. — A single flower of Centaurca jacea with perianth renioved. A, Stamens in normal 

 position ; B, stamens contracted ; c, lower part of tnbnlar perianth ; s, stamens ; a, anther- 

 tube ; g, style ; P, pollen. (Aften Pfeffer, enlarged.) 



It appears that irritability to shock is mainly seen in organs which 

 are capable of movements of variation, while irritability to contact is 

 associated with growth movements. Dionaea perhajos foinns an excep- 

 tion since its seismonastic movements are possibly brought about by 

 growth. There are also plants the sensibility of which is intermediate 

 between irritability to shock and irritability to contact. 



