Cuap. IIL POLEMONIACE. 111 
But several times I watched cases like the following: 
a tendril caught a thin stick by the hooks of one of 
its two extreme branches; though thus held by the 
tip, it still tried to revolve, bowing itself to all sides, 
and by this movement the other extreme branch soon 
caught the stick. The first branch then loosed itself, 
and, arranging its hooks, again caught hold. After a 
time, from the continued movement of the tendril, 
the hooks of a third branch caught hold. No other 
branches, as the tendril then stood, could possibly 
have touched the stick. But before long the upper 
part of the main stem began to contract into an open 
spire. It thus dragged the shoot which bore the 
tendril towards the stick; and as the tendril con- 
tinually tried to revolve, a fourth branch was brought 
into contact. And lastly, from the spiral contraction 
travelling down both the main stem and the branches, 
all of them, one after another, were ultimately brought 
into contact with the stick. They then wound them- 
selves round it and round one another, until the whole 
tendril was tied together in an inextricable knot. 
The tendrils, though at first quite flexible, after 
having clasped a support for a time, become more 
rigid and stronger than they were at first. Thus the 
plant is secured to its support in a perfect manner. 
Lecuminosz.—Pisum sativum.—The common pea 
was the subject of a valuable memoir by Dutrochet,* 
who discovered that the internodes and tendrils 
* Comptes Rendus, tom. xvii. 1843, p, 989. 
