[112]

of leaves being affected greatly by light & darkness makes this movement of a different order from the circumnutation of stems. I think not. We know that light affects movement see my book of stems, not stopping them, but retarding or accelerating them. We might expect that light wd have mor influence on leaves than on stems. (Movements of leaves when excess of light sometimes specialised, as they turn their edges to light) very good) Therefore may be to shoot off water.) I believe shaking at any hour of day cause sleep-movement, so that it does not merely stop movement, but causes a special movement, so does excess of light & I believe cold. In all case known shaking causes sleep movement whether up or down - Is there any case up?? This looks like gravity. No Mimosa pudica go up & some of the acacias & [illeg]. Shaking cause rapid acceleration of Sleep-movement.

[in margin:] Does not alter what period or stop circumnutation, but affects role, will leaves quite affect.

 

[112v]

The diurnal periodic movements which lead to sleep are easily disturbed, too great cold stops them - too much light (as with Oxalis purple-leaved in Hot House & Mimosa pudica) agitation many or most leaves. Especially light, same as Tropaeolum must have been exposed during previous day to a good deal of light: N.B the circumnutation of tendrils & twiners (see to this) stopped by agitation & by cold & dryness. The leaves being specially adapted to turn to light are especially affected by light excess & too little - Tropaeolum too little light during previous day do not descend at night. Shaking affected laminae of leaves I think more than petioles. No not so with Mimosa pudica. see to this.

[in margin:] Is not Averrhoa affected by sun-light.

It causes then to take up quickly position which they wd take up slowly & partially go to sleep - Why it shd accelerate movement, instead of reversing it, I know not perhaps shaking may make some leaves go in reverse direction. I think mechanical action has more effect in disturbing periodical movement of leaves than even light or darkness, (The question is whether the facts of the periodical movements