The Climbing Habit in Antirrhinum majus. 297 
or open spiral and thus possess all the advantages of a typical 
climber. 
Still in spite of this well marked tendency to climb, the main 
stem is usually of normal strength and there is no evident need for 
the plant to develop the climbing habit. 
If the original stimuli inducing the variation were put down to 
high winds and consequent extra friction, to overcrowding and to 
the extra dressing of quicklime, none of these would explain the 
behaviour of the second years’ plants. If we fall back on the 
supposition that these conditions of the habitat were contributory 
causes then their effect was very pronounced and so impressed on 
the plants, that the characters re-appeared, not only in the next 
season’s plants grown from cuttings, but also in the next generation 
grown from seed. 
The appearance of the climbing habit in Antirrhinum is of 
phylogenetic interest. As Darwin 1 points out, four of the seven 
genera of the tribe Antirrhineae, show climbing propensities, viz :— 
Linaria, Maurandia, Lophospermum and Rhodochiton. These are 
chiefly petiole climbers, but Lophospermum scandens v. purpureum 
has sensitive internodes and Maurandia semperftorens has peduncles 
which exhibit feeble revolving movements and are slightly sensitive 
to touch. 
In addition to these, and in the same tribe, Antirrhinum Asarina 
is a weak-stemmed trailing plant, and as noted by Schenck and others, 
the climbing habit appears in several other forms of Antirrhinum. 
In the case under consideration this tendency showed itself in a 
very marked degree. We see, therefore, how strong the climbing 
tendency is within the tribe and it is of interest to find this habit 
asserting itself in non-climbing members of it. That it has not 
been more strongly developed in the petioles is what might be 
expected in a short-stalked form like A. majus and the tendency 
has been transferred to the axillary branches, the basal portions 
of which are affected in a remarkable degree. As we have seen 
many of the branches twine in a manner which, like the peduncles 
of Maurandia, cannot possibly be of service to the plant, but as 
Darwin says “ by a little increase in power through natural selection 
they might easily have been rendered useful.” In this form of 
Antirrhinum majus it has gone a step further. The family trait, 
from some unknown cause, asserts itself and many of the branches 
develop a tendril-like form of a very effective kind. 
1 Darwin, l.c., p. 66. 
