DARWIN ON THE MOVEMENTS OF PLANTS. 507 



leaflets, as seen in Fig. 9, with its lower surface fully exposed to tlie 

 zenith. 



The nyetitropic movements of ten species of the lotus tribe were 

 observed and found to be alike. The main petiole rises a little at 

 night, and the three leaflets rise till they become vertical, and at the 



A. B. 



Fig. 9. TRiFOLnm eepens : A, leaf daring the day ; B, leaf asleep at night. 



same time approach each other. In most of the si^ecies the leaflets 

 rise so much as to press against the stem, and not rarely they become 

 inclined a little inward, with their lower surfaces exposed obliquely to 

 the zenith. The young leaves on the summits of the stems close up at 

 night so much as often to resemble large buds. The stipule-like leaflets, 



A. B. 



Fig. 10. Lotus CRETictrs : A, stem with leaves awake during the day ; B, with leaves asleep at 



night ; ss, stipule-like leaflets. 



which are often of large size, rise up like the other leaflets, and press 

 against the stem (see Fig. 10). The circumnutation of a terminal leaf- 

 let (with the stem secured) was traced during two days, but the move- 



