170 



ACADEMIC BOTANY. 



grow,^^ especially in the Cypress-leaved Morning-Glory, — reach out 

 like the arms of a baby coaxing to be embraced ; they move slowly in 

 a circle until they find a support, then they twine about it, keeping 

 the same direction of motion, which no artifice can reverse or change. 

 The tendrils of the Passion-flower behave in the same way ; but here 

 we see a higher intelligence, — for as soon as a prop is found the tendril 

 fastens by its tip to this stay, and then, coiling upon itself (Fig. 155), 

 it brings the stem close to the support, thus enabling it to climb 

 higher. , 



416. Sensitiveness. — Sensation, the power to feel, has nerves for its 

 seat in the animal ; it is in the nerves of 

 the eye, ear, nose, tongue, and skin that the 

 five senses reside and through which they 

 communicate with the brain. And because 

 even the Oyster has nerves (though it has 

 no brain) it is the custom to say of certain 

 animal actions that they result from Will, 

 which in the lower Orders is called In- 

 stinct, whilst in Man it is called Eeason. 

 We find no nerves in plants, but in many 

 of them a high degree of sensitiveness. In 

 the Pea Family, which includes the Mimosa 

 and Sensitive Plants, this is finely exhibited. 

 The Mimosa gets its botanical name (Gr. 

 mimos, a mimic) from the animal-like fac- 

 ulty of moving and folding its leaves at the 

 •-slightest touch; they close upward, too, 

 contrary to the law of gravitation. The sen- 

 sitiveness of stamens and pistils at flower- 

 ing-time have already been noticed (303). 

 The stamens of the Eook-rose (Fig. 243) 

 are so irritable that if touched during sun- 

 shine they spread out upon the petals. 



417. Cunning. Sport. Free Locomotion. 

 — We have seen in Lesson XVI. with what 

 cunning the Fly-trap, Nepenthes, and Sar- 

 racenia entrap flies and. other insects for the 

 sake of obtaining animal food. Their move- 

 ments, however, depend somewhat upon 



(ffiltaSii^iJrf'^ef"''''"'™* °"t='^« ^°^°^' 'i'^^ ^^°^^ °f t'^" sensitive 

 e vm lemum gore). plants ; the fly must alight on the plant to 



arouse it to action. But we see an independent motion in the Tele- 

 graph Plant of East India, which belongs to the Pea Family and has 

 ternate leaves, like our common Tick Trefoils. The end leaflet slowly 

 changes its position, following the light; the two small leaflets below 

 it move spontaneously with quick jerks up and down in elliptical 

 curves, which give the plant its specific name [gyrans). One leaflet 

 descends whilst the other rises, as if they were sporting with each other. 

 Cold water poured on the plant stops the motion (as it would stop that 

 of any other dancer), but with returning warmth it begins again. It 

 is most rapid in fair, moderate weather, and ceases at night. The free 

 locomotion of the spores of the Algse we have known from the begin- 

 ning (Lesson V.). Their gambols are less surprising after we examine 



