34 TWINING PLANTS. Chap. I. 



soandens twines, as I have described, from left to right, 

 another species in South Brazil twines in an opposite 

 direction. It would have been an anomalous circum- 

 stance if no such cases had occurred, for different 

 individuals of the same species, namely, of Solamim 

 dulcamara (Dutrochet, tom. xix. p. 299), revolve and 

 twine in two directions : this plant, however, is a most 

 feeble twiner. Loasa aurantiaca (Leon, p. 351) offers 

 a much more curious case : I raised seventeen plants : 

 of these eight revolved in opposition to the sun and 

 ascended from left to right ; five followed the Sun and 

 ascended from right to left ; and four revolved and 

 twined first in one direction, and then reversed their 

 course,* the petioles of the opposite leaves affording a 

 point d'appui for the reversal of the spire. One of 

 these four plants made seven spiral turns firom right 

 to left, and five turns from left to right. Another 

 plant in the same family, the Scyfhanthus elegwns, 

 habitually twines in this same manner. I raised 

 many plants of it, and the stems of all took one 

 turn, or occasionally two or even three turns in 

 one direction, and then, ascending for a short space 

 straight, reversed their course and took one or two 

 turns in an opposite direction. The reversal of 

 the curvature occurred at any point in the stem, 

 even in the middle of an intemode. Had T not 

 seen this case, I should have thought its occurrence 



* I raised nine plante of the of these also revetsed theii spire 

 hybrid Loasa Serhertii, and si^ in ascending a suppoit. 



