CHAPTER VII 



NATURE'S WOODCRAFT: A CHAPTER OiV STEMS 



Sap-laden stems, of forms grotesque and weird, 

 That creep, and climb, and twine, and hang in air. 



WHAT is a stem ? The term in popular language is confined to those 

 parts of the plant which rise above the ground, but popular ideas 

 are not always satisfactory or exact. "We have seen that roots also may rise 

 above the ground ; and is not a tuber an instance of a stem which grows 

 beneath the soil ? The popular definition, then, will not answer. Of 

 botanical definitions, Professor Thome's is. perhaps, as 

 satisfactory as any. " The stem, in its various forms," 

 he says (Lehrbuch, p. 49), ' : is that part of the plant 

 which bears the leaves, flowers, and fruits." This is, on 

 the whole, a sufficient definition. 



Before treating in detail of these " various forms," it 

 would be well to make a few remarks on the structure 

 of the stem. When dealing, on a former occasion, with 

 the cells and vessels of plants, we named and described 

 the three great classes into which all permanent tissues 

 may -be divided viz. Fundamental or Ground Tissue, 

 the Fibro-vascular System, and Epidermal Tissue ; and 

 we saw that each of these classes is represented in 

 every well-developed foliage leaf. The annexed diagram 

 (fig. 257) has been prepared with the view of illustrating 

 the manner in which these tissues and vessels are 

 distributed through the stem of an ordinary dicotyle- 

 donous plant. The figure, indeed, represents an actual 

 model which was made for us for lecture purposes, and 

 which consists of a column of wax, not unlike an altar 

 candle, but furnished with eight large wicks instead of 

 one, the wicks being arranged in a circle, at about 

 equal distances from each other. Fitting closely round 

 the column is a cylinder of stout paper. 



"We will suppose that this column represents the erect 

 and very young stem of a Flowering Plant say a Sun- 



FIG. 257. VESSELS. 



Diagram illustrating the 



arrangement of thefibro- 



vascular bundles in a 



dicotyledonous stem. 



205 



