32 TWINING PLANTS. Chap. I. 



(Dicotyledons, continued.) 



H. II. 



. .. n , . , , . ln nrt I (a distinct shoot, very 



April, 2nd circle was made in 12 20 { x , * 



[ young, on same plant) 



3rd . 7 30 



In this latter circlo, 



the semicircle from 

 the light took 5 hrs. 

 23 m., and to the 

 light 2 hrs. 37 min. : 

 difference 2 hrs 46 m. 



Aristolochia gigas (Aristolochiacese) moves against the sun. 



H. m. 



July 22, 1st circle was made in . 8 (rather young shoot) 

 23, 2nd .7 15 



24, 3rd .50 (about) 



4th .80S 



)> J."-"- if ,, 



In the foregoing Table, which includes twining 

 plants belonging to widely different orders, we see 

 that the rate at which growth travels or circulates 

 round the axis (on which the revolving movement 

 depends), differs much. As long as a plant remains 

 under the same conditions, the rate is often remarkably 

 uniform, as with the Hop, MiJcania, Phaseolus, &c. The 

 Seyphanthus made one revolution in 1 hr. 17 m., and 

 this is the quickest rate observed by me ; but we shall 

 hereafter see a tendril-bearing Passiflora revolving 

 more rapidly. A shoot of the Akebia quinata made a 

 revolution in 1 hr. 30 m., and three revolutions at the 

 average rate of 1 hr. 38 m. ; a Convolvulus made two 

 revolutions at the average of 1 hr. 42 m., and Phaseolus 

 vulgaris three at the average of 1 hr. 57 m. On the 

 other hand, some plants take 24 hrs. for a single 

 revolution, and the Adhadota sometimes required 

 48 hrs. ; yet this latter plant is an efficient twiner. 



