122 TENDRIL-BEARERS. Cuap. III. 
from one locality alone, viz. Hampshire; and it is not 
improbable that plants growing under different condi- 
tions might have their leaves a little more or less 
changed into true tendrils. 
Whilst the plant is quite young, the first-formed 
leaves are not modified in any way, but those next 
formed have their terminal leaflets reduced in size, 
and soon all the leaves assume the structure repre- 
sented in the following drawing. This leaf bore nine 
leaflets; the lower ones being much subdivided. The 
terminal portion of the petiole, about 13 inch in 
length (above the leaflet f), is thinner and more 
elongated than the lower part, and may be considered 
as the tendril. The leaflets’ borne by this part are 
greatly reduced in size, being, on an average, about 
the tenth of an inch in length and very narrow; one 
small leaflet measured one-twelfth of an inch in 
length and one-seventy-fifth in breadth (2116 mm. and 
‘339 mm.), so that it was almost microscopically minute. 
All the reduced leaflets have branching nerves, and 
terminate in little spines, like those of the fully de- 
veloped leaflets. Every gradation could be traced, 
until we come to branchlets (as a and d in the figure) 
which show no vestige of a lamina or blade. Occasion- 
ally all the terminal branchlets of the petiole are in 
this condition, and we then have a true tendril. 
The several terminal branches of the petiole bearing 
the much reduced leaflets (a, b, ¢, d) are highly 
sensitive, for a loop of thread weighing only the one- 
sixteenth of a grain (4:05 mg.) caused them to become 
