516 



MODIFIED CIRCUMNUTATION. 



CHAP. X. 



Fig. 191 



which was already curved 36 beneath the horizon, was observed 

 from 11 A.M. July 22nd to the 27th, by which latter date it 

 had become vertically dependent. Its course during the first 

 12 h. is shown in Fig. 190, and its position on the three 

 succeeding mornings until the 25th, 

 when it was nearly vertical. During 

 the first day the peduncle clearly 

 circumnutated, for it moved 4 times 

 down and 3 times up; and on each 

 succeeding day, as it sank downwards, 

 the same movement continued, but 

 was only occasionally observed and 

 was less strongly marked. It should 

 ^ stated tha t these peduncles were 



cumnutating movement of observed under a double skylight in 

 peduncle, whilst the flower- the house, and that they generally 



TrifoliumMerraneum: cir- 



Fig. 192. 



of the calyx still visible ; slowly than those on plants growing 

 traced from 8 A.M. July out of doors or in the greenhouse. 

 26th to 9 A.M on 27th. The movement of another vertically 

 v^l"s fiX p dependent peduncle with the flower- 

 near flower- head. head standing half an inch above the 



ground, was traced, and again when 



it first touched the ground; in both cases irregular ellipses 

 were described every 4 or 5 h. A peduncle on a plant which 

 had been brought into the house, 

 moved from an upright into a ver- 

 tically dependent position in a 

 single day; and here the course 

 during the first 12 h. was nearly 

 straight, but with a few well-mark* d 

 Trifo!iu,n subterraneum : move- zigzags which betrayed the essential 

 ment of same peduncle, with nature of the movement. Lastly, 

 flower-head completely buried the circumnutation of a peduncle 



tra - d *"* 51h - whilst 



the act of burying itself obliquely 

 in a little heap of sand. After it had buried itself to such a 

 depth that the tips of the sepals were alone visible, the above 

 figure (Fig. 191) was traced during 25 h. When the flower- 

 head had completely disappeared beneath the sand, another 

 tracing was made during 11 h. 45m. (Fig. 192); and here again 

 we see that the peduncle was circumnutating. 



