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
irregular line, with little loops in its course. A young peduncle
1.5 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 adjoining 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, {21} I rubbed
two young peduncles (1.5 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 these sides; in 24 hrs. subsequently, they straightened
themselves. Next day they were rubbed on the opposite sides, and
they became perceptibly curved towards these sides. Two other and
younger peduncles (three-fourths of an inch in length) were lightly
rubbed on their adjoining sides, and they became so much curved
towards one another, that the arcs of the bows stood at nearly right
angles to their previous direction; and this was the greatest
movement seen by me. Subsequently they straightened themselves.
Other peduncles, so young as to be only three-tenths of an inch in
length, became curved when rubbed. On the other hand, peduncles
above 1.5 inch in length required to be rubbed two or three times,
and then became only just perceptibly bowed. Loops of thread
suspended on the peduncles produced no effect; loops of string,
however, weighing 0.82 and 1.64 of a grain sometimes caused a slight