Fig. 33. Leaf of Sensitive Plant in its usual position.
Fig. 34. Leaf of Sensitive Plant, leaflets at a beginning to close after being gently touched.
There are plants, however, which move so quickly that you can see them close up their leaves at once at the slightest touch. This is the case in the Sensitive Plant (fig. 33), and if you only tap one of its tiny leaflets with a straw, that pair of leaflets will immediately fold up, then the next pair, and the next, till the whole leaf has closed, when it drops quickly down (see fig. 35), this movement only taking a moment. If the shock is great, all the leaves on the plant will close up instantly, and they move so quickly that you can hardly see them doing it.
