HOW PLANTS CLIMB. 207 



firmly glue together 50 or 60 fibres of flax or wool in a mass. This 

 power is used naturally by this species to fasten itself to the 

 forest-trees of North America, which are covered with mosses, 

 lichen, and other rugged and rough organisms. 



3. — Tendrils luhich are modified floiver-pcdtuicles. 



Excellent examples of such tendrils are seen in the Vine, the 

 Virginia Creeper, and the Passion-flower. The first two belong to 

 one order, the Vitacece. In these the action is much the same as 

 in the cases of tendrils which are modified leaves 



In the Vine the tendril is two-branched, one branch always 

 having a scale at its base. Rubbing causes the branches to bend, 

 but they will afterwards become straight again. A tendril clasp- 

 ing any object contracts spirally. Of this, later on. There is 

 clear spontaneous movement in the tendrils. We can trace 

 every single stage of gradation from the state of flower-stalk to 

 that of a true tendril ; from one bearing 30 or 40 flower-buds 

 even to a full-sized perfect tendril bearing one flower-bud ! 

 Hence we cannot question the nature of the tendril in the Vine. 

 Where the flower-stalk and the flower-tendril exist together, the 

 latter is always at such an angle with the former that it assists 

 later on in carrying the burden of the fruit. 



In the Virginia Creeper there is no revolving of either inter- 

 nodes or tendrils ; only a movement away from the light to the 

 dark, a process seen in several tendril-bearers. The tendrils are 

 specially adapted for attachment to a flat wall or other surface by 

 bringing their hooked tips into contact with it. These then 

 develop the well-known discs or cushions of a bright-red tint. 

 These undoubtedly secrete a viscid fluid, inasmuch as they can 

 cling to smooth polished surfaces, such as an Ivy-leaf or painted 

 wood. Warm water with dilute acetic acid and alcohol will not 

 loosen any flinty particles that may have become attached to the 

 discs, but warm, essential oils will loosen them entirely, pointing 

 to a resinous fluid as the one secreted. Discs are not developed 

 except under the stimulus of contact. The attached tendrils 

 contract spirally ; unattached ones do not, but in time shrivel up 

 and drop away. The spirally-contracted tendril becomes very 

 elastic. At first it is brittle and weak, but soon acquires strength 

 and increases in thickness. It dies during the next winter, but 



