166 REVIEWS. 



tions being now almost freed from the constraint of gravity, 

 and allowed to act freely. With the Wistaria, on the other 

 hand, a long, horizontal shoot wound itself at first, in a very 

 close spire, which remained unchanged ; but subsequently, as 

 the shoot grew, it made a much more open spire. With all 

 the many plants which were allowed freely to ascend a sup- 

 port, the terminal internodes made at first a close spire ; and 

 this, during windy weather, well served to keep the shoots in 

 contact with their support ; but as the penultimate internodes 

 grew in length, they pushed themselves up for a considerable 

 space (ascertained by colored marks on the shoot and on the 

 support) round the stick, and the spire became more open. 



" If a stick which has arrested a revolving shoot, but has 

 not as yet been wound round, be suddenly taken away, the 

 shoot generally springs forward, showing that it has continued 

 to press against the stick. If the stick, shortly after having 

 been wound round, be withdrawn, the shoot retains for a time 

 its spiral form, then straightens itself, and again commences 

 to revolve. The long, much-inclined shoot of the Ceropegia 

 previously alluded to offered some curious peculiarities. The 

 lower and older internodes, which continued to revolve, had 

 become so stiff that they were incapable, on repeated trials, of 

 twining round a thin stick, showing that the power of move- 

 ment was retained after flexibility had been lost. I then 

 moved the stick to a greater distance, so that it was struck by 

 a point 2 J inches from the extremity of the penultimate inter- 

 node ; and it was then neatly wound round by this part and 

 by the ultimate internode. After leaving the spirally wound 

 shoot for eleven hours, I quietly withdrew the stick, and in 

 the course of the day the curled part straightened itself and 

 re-commenced revolving ; but the lower and not curled portion 

 of the penultimate internode did not move, a sort of hinge 

 separating the moving and the motionless part of the same 

 internode. After a few days, however, I found that the 

 lower part of this internode had likewise recovered its revolv- 

 ing power. These several facts show, that, in the arrested 

 portion of a revolving shoot, the power of movement is not 

 immediately lost, and that when temporarily lost it can be re- 



