68 LEAF-CLIMBERS. Cuap. II. 
which alone has the power of revolving; so that they 
could be brought only ‘by accident into contact with 
any neighbouring object. Nevertheless (and this is 
the remarkable fact) the flower-peduncles, whilst 
young, exhibit feeble revolving powers, and are slightly 
sensitive to a touch. Having selected some stems 
which had firmly clasped a stick by their petioles, 
and having placed a bell-glass over them, I traced 
the movements of the young flower-peduncles. The 
tracing generally formed a short and extremely irre- 
gular line, with little loops in its course. A young 
peduncle 14 inch in length was carefully observed 
during a whole day, and it made four and a half 
narrow, vertical, irregular, and short ellipses—each 
at an average rate of about 2 hrs. 25 m. An ad- 
joining peduncle described during the same time 
similar, though fewer, ellipses. As the plant had 
occupied for some time exactly the same position, 
these movements could not be attributed to any change 
in the action of the light. Peduncles, old enough for 
the coloured petals to be just visible, do not move. 
With respect to irritability,* I rubbed two young 
peduncles (14 inch in length) a few times very lightly 
with a thin twig; one was rubbed on the upper, and 
the other on the lower side, and they became in 
between 4 hrs. and 5 hrs. distinctly bowed towards 
* It appears from A. Kerner’s when they are rubbed or shaken: 
interesting observations, that the Die Schutzmittel des Pollens, 
flower-peduncles ofalargenumber 1873, p. 34. 
of plants are irritable, and bend 
