76 LEAF-CLIMBERS. Cuap. 1. 
portion of the petiole can seize a support. I have 
seen a substance as soft as a withered blade of grass 
caught. Petioles which have clasped any object 
ultimately become rather thicker and more cylindri- 
cal. On lightly rubbing several petioles with a twig, 
they became perceptibly curved in Lhr. 15.m., and 
subsequently straightened themselves. A stick gently 
placed in the angle between two sub-petioles excited 
them to move, and was almost clasped in 9 hrs. A 
loop of thread, weighing one-eighth of a grain, caused, 
after 12 hrs. and before 20 hrs, had elapsed, a consider- 
able curvature ; but it was never fairly clasped by the 
petiole. The young internodes are in continual move- 
ment, which is considerable in extent, but very irregu- 
lar; a zigzag line, or a spire crossing itself, or a figure 
of 8 being formed. The course during 12 hrs., when 
traced on a bell-glass, apparently represented about 
four ellipses. The leaves themselves likewise move 
spontaneously, the main petioles curving themselves 
in accordance with the movements of the internodes; 
so that when the latter moved to one side, the petioles 
moved to the same side, then, becoming straight, 
reversed their curvature. The petioles, however, 
do not move over a wide space, as could be seen when 
a shoot was securely tied to a stick. The leaf in this 
case followed an irregular course, like that made by 
the internodes. 
Adlumia cirrhosa.—I raised some plants late in the 
summer; they formed very fine leaves, but threw 
up no central stem. The first-formed leaves were not 
