Cuapr. I. TWINING PLANTS. 41 
when we reflect how little the leaves are developed on 
the young and thin revolving internodes. It is all’ 
the more remarkable, as botanists believe (Mohl, 
p- 119) that twining plants are but little sensitive 
to the action of light. 
I will conclude my account of twining plants by 
giving a few miscellaneous and curious cases. With 
most twining plants all the branches, however many 
there may be, go on tevolving together; but, ac- 
cording to Mohl (p. 4), only the lateral branches of 
Tamus elephantipes twine, and not the main stem. 
On the other hand, with a climbing species of Aspa- 
ragus, the leading shoot alone, and not the branches, 
revolved and twined ; but it should be stated that the 
plant was not growing vigorously. My plants of 
Combretum argentewm and C. purpureum made nume- 
rous short healthy shoots; but they showed no signs 
of revolving, and I could not conceive how these 
plants could be climbers ; but at last C. argentewm put 
forth from the lower part of one of its main branches 
a thin shoot, 5 or 6 feet in length, differing greatly 
in appearance from the previous shoots, owing to its 
leaves being little developed, and this shoot re- 
volved vigorously and twined. So that this plant 
produces shoots of two kinds. With Periploca Greca 
(Palm, p. 48) the uppermost shoots alone twine. 
Polygonum convolvulus twines only during the middle 
of the summer (Palm, p. 48, 94); and plants growing 
vigorously in the autumn show no inclination to 
climb. The majority of Asclepiadacee are twiners ; 
3 
