280 Scientific Intelligence. 
Of Leaf-climbers, no instance is more familiar than that of Clem- 
atis or Virgin’s Bower. Little more was known of them than that they 
climbed by curling their petioles (common or partial) around neighboring 
objects. Mr. Darwin made observations upon eight species of Clematis, 
seven of Tropeolum, the common species of Maurandia, ; 
mum, Fumaria, ‘ Gloriosa and Flagellaria, which 
climb by a tendril-like production of the tip of the leaf. From the sum- 
have clasping petioles, and those of four families climb by the tips of 
their leaves. In almost all of them the young internodes revolve, in 
me of them as extensively as in twining plants,—the movement being 
plainly serviceable in bringing the petioles or the tips of the leaves into 
contact with surrounding objects. Those whose shoots revolve most 
freely are also capable of twining spirally around a support; but when 
for a few times, when in of it bends to the rub- 
bed side, afterwards becoming straight again; or by leaving the body In 
contact it is permanently cl by the footstalk. So sensitive are some 
, , young petioles are sensitive. 
Take the cultivated Clematis Viticella for an illustration of the mode in i 
the 
