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IX. 
THE CLIMBING AND TWINING PLANTS OF THE SOUTH 
MIDLANDS. 
By James Saunders, A.L.S. 
Read at Watford, 29 th March, 1904. 
It is intended in the following paper to enumerate the species, 
and describe some of the peculiarities, of the climbing and twining 
plants which are to be met with in this district, making only such 
references to exotic forms as may be necessary to the adequate 
illustration of the subject. 
The leading idea of the scandent habit in plants is the acquisition 
of the power to reach the light and air with a minimum expenditure 
of energy and of formative material. This is attained by an 
unequal growth of the opposite sides of an axis, and by a revolving 
movement of the apex known as circumnutation, or by the develop¬ 
ment of tendrils, which may be modified foliar organs or specialized 
branches. 
Some of the species that possess one or more of these peculiarities 
are annual, perishing after a brief existence; examples of these 
are furnished by the Fumitories. Others are perennial and possess 
a permanent rootstock, the stems dying down to the surface every 
Autumn. Such species develop their branches very rapidly in the 
Spring-time, and, as in the case of the Biyonies, they are able in 
a few weeks to reach the top of the hedgerows, from the base of 
which their annual growth has commenced. 
The primary internodes of climbing stems do not possess the 
power of twining. (See Sach’s ‘Text-book of Botany,’ 2nd ed., 
p. 862.) 
Other peculiarities of the scandent habit are the suppression or 
subversion of the forces of heliotropism and apogeotropism, which 
usually govern the growth of the ascending axes of plants. By 
the influence of heliotropism the stems as well as the upper surfaces 
of leaves turn towards the incident light; by apogeotropism the 
ascending axis grows erect, or as nearly so as its environment 
permits. The adventitious roots of the ivy stem furnish an illus¬ 
tration of negative heliotropism, in that they turn from the light 
in their efforts to attach themselves to the object near which they 
are growing. Another familiar example of this habit is the graceful 
creeper Ampelopsis Veitchii, of Japanese origin, which has become 
thoroughly acclimatized in this country. 
For convenience climbing plants may he grouped according to 
the organs which are modified for that purpose. 
Stems .—The circular movement of the stem in its endeavour to 
find a support is limited to the upper portion, usually to the last 
two or three internodes. The length of time occupied in making 
a single revolution varies in different genera, and is also influenced by 
