Ill 



ANATOMY STUDY OF THE SHOOT 



29 



EXPT. 20. Obtain a portion of the Hop-plant or Honeysuckle with 

 its support. Note 



(i) How and in what direction the stem has moved. Compare with 

 a piece of the Scarlet Runner and Bindweed. 



(ii) Note the difference in the direction of twining. 



EXPT. 21. Obtain from a hedgerow or garden a piece of Clematis 

 showing the sensitive leaf-stalks. Examine how the stalks clasp the 

 support. 



EXPT. 22. Obtain a tendril-bearing plant, such as the Vine, Vetch, 

 Sweet Pea, Cucumber, or Bryony. Examine to see what parts of the 

 plant have been modified in the production of the tendril. Compare 

 with a portion of the Virginian Creeper. 



The Shape of the Stem. Stems may be round or cylin- 

 drical^ as in the Lily ; triangular, as in the flower stem of the 

 Daffodil ; square, like the Deadnettle ; or ribbed, like the Wall- 

 flower (Figs. 28 32). 



FIG. 28. 

 Round stem, 

 with section. 



FIG. 29. 

 Square stem, 

 with section. 



FIG. 30. 



Ribbed 



stem, with 



section. 



FIG. 31. 

 Triangular 

 stem, with 



section. 



FIG. 32. 



Coarsely- 

 ribbed stem, 

 with section. 



Some stems are solid at the nodes, but hollow at the internodes, 

 e.g.* FooFs-Parsley. Others are solid throughout as in the 

 Wallflower. 



Surface of the Stem. Stems differ not only in their shapes 

 but also as regards the nature of their surfaces. Many stems 

 are completely covered with hairs, prickles, or thorns. If the 

 surface is smooth, it is termed glabrous ; if hairs are present, 

 hairy. 



