8 TWINING PLANTS. Cuap. I. 
possible that the twisting of the axis of the Hop three 
times should have caused thirty-seven revolutions. 
Moreover, the revolving movement commenced in the 
young internode before any twisting of its axis could 
be detected. The internodes of a young Siphomeris 
and Lecontea revolved during several days, but became 
twisted only once round their own axes. The best 
evidence, however, that the twisting does not cause the 
revolving movement is afforded by many leaf-climbing 
and tendril-bearing plants (as Pisum sativum, Echino- 
cystes lobata, Bignonia capreolata, Hecremocarpus scaber, 
and with the leaf-climbers, Solanwm jasminoides and 
various species of Clematis), of which the internodes are 
not twisted, but’ which, as we shall hereafter see, re- 
gularly perform revolving movements like those of true 
twining-plants. Moreover, according to Palm (pp. 80, 
95) and Mohl (p: 149), and Léon,* internodes may 
occasionally, and even not very rarely, be found which 
are twisted in an opposite direction to the other inter- 
nodes on the same plant, and to the course of their 
revolutions ; and this, according to Léon (p. 356), is 
the case with all the internodes of a certain variety of 
Phaseolus multiflorus. Internodes which have become 
twisted round their own axes, if they have not ceased 
to revolve, are still capable of twining round a support, 
as I have several times observed. 
Mohl has remarked (p. 111) that when a stem twines 
round a smooth cylindrical stick, it does not become 
* ‘Bull. Bot. Soc, de France, tom. v. 1858, p. 356. 
