28 



BOTANY FOR BEGINNERS 



CHAP. 



Is used for climbing. These organs, with their ready response to 

 any contact and their power of turning round and clinging to 

 objects, are the most highly developed in the class of climbing 

 plants. Tendrils are formed from various parts of plants ; thus, 

 in the Passion flower it is a whole branch transformed ; the 

 tendril of the Vine is a flower-stalk ; that of the Sweet Pea, the 

 whole blade of a leaf ; that of the Cucumber and its allies arise 



by the alteration of the leaf-like 

 bodies found at the base of the 

 leaf-stalk and known as stipules. 

 The tendrils, like the twining stem, 

 move round and round in search of 

 a support. 



Some tendrils, when their move- 

 ments are arrested by a support, 

 form adhesive masses at their free 

 ends, as in the Virginian creeper, 

 which is so often seen covering the 

 sides of houses. Soon after the 

 tendrils of the Virginian creeper 

 have laid themselves down, as it 

 were, upon a wall, their tips swell, 

 become red and form little swollen 

 cushions. On the parts in con- 

 tact with the wall, small pro- 

 jections are produced which in- 

 sinuate themselves into every little 

 crevice and seem to give out a 

 cement which binds them to the 

 support (Fig. 27). 



R 



FIG. 27. Virginian Creeper. 

 R, R, stem tendrils. (Three- 

 fourths nat. size.) 



EXPT. 1 8. Obtain a piece of Ivy 

 from an old wall ; examine it. Note 

 the following points 



(i) That a portion of the wall has come away with the roots, 

 (ii) That the roots grow on a portion of the stem which is turned 

 away, from the light. 



(iii) That the root dries up, and forms a beard on the stem. 



EXPT. 19. Examine branches of the Rose or Bramble. Notice 

 (i) The prickles ; pull one or two off and see how much of the 

 branch comes away with them. 



(ii) Prickles may be used for protection as well as for climbing. 



