Cuap. IL. BIGNONIACE. 91 
a second in 2 hrs.55m. By these combined move- 
ments of the internodes, petioles, and grapnel-like 
tendrils, the latter are soon brought into contact with 
surrounding objects. When a shoot stands near an 
upright stick, it twines regularly and spirally round 
it. As it ascends, it seizes the stick with one of its 
tendrils, and, if the stick be thin, the right- and left- 
hand tendrils are alternately used.- This alternation 
follows from the stem necessarily taking one twist 
round its own axis for each completed circle. 
The tendrils contract spirally a short time after 
catching any object; those which catch nothing merely 
bend slowly downwards. But the whole subject of 
the spiral contraction of tendrils will be discussed 
after all the tendril-bearing species have been de- 
scribed. 
Bignonia littoralis—The young internodes revolve 
in large ellipses. An internode bearing immature 
tendrils made two revolutions, each in 3 hrs. 50 m.; 
but when grown older with the tendrils mature, it 
made two ellipses, each at the rate of 2 hrs. 44 m. 
This species, unlike the preceding, is incapable of 
twining round a stick: this does not appear to be 
due to any want of flexibility in the internodes or 
to the action of the tendrils, and certainly not to 
any want of the revolving power; nor can I account 
for the fact. Nevertheless the plant readily ascends 
a thin upright stick by seizing a point above with its 
two opposite tendrils, which then contract spirally. If 
the tendrils seize nothing, they do not become spiral. 
