416 CLIMBING PLANTS. 
the Bryony (Fig. 92) safely rode out the gale, like a ship 
with two anchors down, and with a long range of cable 
ahead to serve as a spring as she surges to the storm. When 
an uncaught tendril contracts spirally the spire always runs 
in the same direction from tip to base. A tendril, on the 
other hand, which has caught a support by its extremity, 
invariably becomes twisted in one part in one direction, and 
in another part in the opposite direction; the oppositely 
turned spires being separated by short, straight portions. 
Sometimes the 
spires of a ten- 
Fig. 91. 
dril alternately 
turn as many as 
five times in op- 
posite directions, 
with straight 
portions between 
them; even seven 
or eight have 
been seen by M. 
Léon. Whether 
few spires, or 
many, there are 
as many in one 
‘Woodbine. 
direction as in 
the other. To give an illustration; when a haberdasher 
winds up ribbon for a customer he does not wind it into a 
single coil; for. if he did, the ribbon would twist itself as 
many times as there were coils; but he winds it into a figure 
of eight on his thumb and little finger, so that he alternately 
takes turns in opposite directions, and thus the ribbon is not 
twisted. So it is with tendrils, with this sole difference, 
that they take several consecutive turns in one direction, and 
then the same number in an opposite direction ; but in both 
cases the self-twisting is equally avoided. Passiflora gracilis 
has the most sensitive tendrils which were seen; a bit of 
