Cuar. IIL, POLEMONIACE. 109 
time. In a plant placed in the hot-house and grow- 
ing vigorously, a tendril revolved for not longer than 
36 hours, counting from the period when it first became 
sensitive; but during this period it probably made at 
least 27 revolutions. 
When a revolving tendril strikes against a stick, 
the branches quickly bend round and clasp it. The 
little hooks here play an important part, as they 
prevent the branches from being dragged away by the 
rapid revolving movement, before they have had time 
to clasp the stick securely. - This is especially the case 
when only the extremity of a branch has caught 
hold of a support. As soon as a tendril has bent 
round a smooth stick or a thick rugged post, or has 
come into contact with planed wood (for it can adhere 
‘temporarily even to so smooth a surface as this), the 
same peculiar movements may be observed as those 
described under Bignonia capreolata and Eccremocar- 
pus. ‘The branches repeatedly lift themselves up and 
down; those which have their hooks already directed 
downwards remaining in this position and securing 
the tendril, whilst the others twist about until they 
succeed in arranging themselves in conformity with 
every irregularity of the surface, and in bringing 
their hooks into contact witb. the wood. The use of 
the hooks was well shown by giving the tendrils 
tubes and slips of glass to catch; for these, though 
temporarily seized, were invariably lost, either during 
the re-arrangement of the branches or ultimately when 
spiral contraction ensued. 
