Cuap. V. CONCLUDING REMARKS. 203 
first rises vertically up, with its branches divergent 
and with the terminal hooks turned outwards; the 
young shoot at the extremity of the stem is at the 
same time bent to one side, so as to be out of the way. 
The young leaves of Clematis, on the other hand, 
prepare for action by temporarily curving themselves 
downwards, so as to serve as grapnels. 
Secondly, if a twining plant or a tendril gets by 
any accident into an inclined position, it soon bends 
upwards, though secluded from the light. The guid- 
ing stimulus no doubt is the attraction of gravity, as 
Andrew Knight showed to be the case with germinat- 
ing plants. Ifa shoot of any ordinary plant be placed 
in an inclined position in a glass of water in the dark, 
the extremity will, in a few hours, bend upwards; and 
if the position of the shoot be then reversed, the 
downward-bent shoot reverses its curvature; but if 
the stolon of a strawberry, which has no tendency to 
grow upwards, be thus treated, it will curve downwards 
in the direction of, instead of in opposition to, the 
force of gravity. As with the strawberry, so it is 
generally with the twining shoots of the Hibbertia 
dentata, which climbs laterally from bush to bush; for 
these shoots, if placed in a position inclined downwards, 
show little and sometimes no tendency to curve up- 
wards. 
Thirdly, climbing plants, like other plants, bend 
towards the light by a movement closely analogous to 
the incurvation which causes them to revolve, so that 
their revolving movementis often accelerated or retarded 
