252 FREAKS OF PLANT LIFE. 



young petioles, near the top of the plant, rise to such 

 an extent as to be nearly parallel to the stem, whilst 

 the older ones rise considerably. In the evening the 

 rising of the petioles is almost completed before the 

 terminal leaflet begins to fall. Whilst the plant is 

 awake — that is, during the day-time, the leaflets arc 

 in constant motion ; but, after six o'clock in the 

 evening, when the nocturnal descent has commenced, 

 the direction is almost directly and straightly down- 

 wards. After the leaflets are completely depressed 

 for the night they move very little or not at all. The 

 little lateral leaflets do not appear to sleep. They 

 were seen in motion, jerking as they usually do, at 

 ten and at eleven o'clock at night. At one o'clock in 

 the morning the leaflets were still jerking rapidly. 

 At half-past three the jerking was not observed. At 

 half-past eight in the morning it had commenced 

 jerking again. " This leaflet, therefore, was moving 

 during the whole night, and the movement was by 

 jerks up to one a.m. (and possibly later), and again at 

 half-past eight a.m." 



Similar nocturnal movements, such as the eleva- 

 tion of the petioles, and the vertical depression of the 

 leaves have been observed in several other plants 

 allied to the above, belonging to the same great 

 natural order. 



In Acacia Farnesiana the difference between the 

 appearance of a waking and sleeping plant is most 



