262 HOW CROPS GROW. 



other. If the rudimentary leaves of a bud be represented 

 by a nest of flower-pots, the smaller placed within, the 

 larger, the stem may be signified by a rope of India- 

 rubber passed through the holes in the bottom of the 

 pots. The growth of the stem may now be shown by stretch- 

 ing the rope,whereby the pots are brought away from each 

 other, and the whole combination is made to assume the char- 

 acter of a fully developed stem, bearing its leaves at regular 

 intervals ; with these important differences, that the por- 

 tions of stem nearest the root extend more rapidly than 

 those above them, and the stem has within it the material 

 and the mechanism for the continual formation of new 

 buds, which unfold in successive order. 



In fig. 45, which represents the two terminal buds of a 

 lilac twig, is shown not only the external appearance of 

 the buds, which are covered with leaf-like scales, imbricated 

 like shingles on a roof; but, in the section, are seen the 

 edges of the undeveloped leaves attached to the conical 

 axis. All the leaves and the whole stem of a twig of one 

 summer's growth thus exist in the bud, in plan and in 

 miniature. Subsequent growth is but the development 

 of the plan. 



In the flower-bud the same structure is manifest, save 

 that the rudimentary flowers and fruit are enclosed within 

 the leaves, and may often be seen plainly on cutting the 

 bud open. 



Culms ; Nodes ; Internodes. The grasses and the com- 

 mon cereal grains have single, unbranched stems, termed 

 culms in botanical language. The leaves of these plants 

 clasp the stem entirely at their base, and at this point is 

 formed a well-defined, thickened knot or node in the stem. 

 The portions of the stem between these nodes are termed 

 internodes. 



Branching Stems* Other agricultural plants besides 

 those just mentioned, and all the trees of temperate cli- 



