82 



ARRANGEMENT OF FLOWERS ON THE STEM. [LESSON 11. 



the Stem ; for its terminal bud, being changed into a blossom, can 

 no more lengthen in the manner of a leaf-bud. Any further growth 



must be from axillary buds developing into branches. If such 

 branches are leafy shoots, at length terminated by single blossoms, 

 the inflorescence still consists of solitary flowers at the summit of the 

 stem and branches. But if the flowering branches bear only bracts 

 in place of ordinary leaves, the result is the kind of flower-cluster 

 called I 



216. A Cyme. This is commonly a flat-topped or con- 

 vex flower-cluster, like a corymb, only the blossoms are 

 from terminal buds. Fig. 164 illustrates the simplest 

 cyme in a plant with opposite leaves, namely, with three 

 flowers. The middle flower, a, terminates the stem ; 

 the two others, 6 h, terminate short branches, one from 

 the axil of each of the uppermost leaves; and being 

 later than the middle one, the flowering proceeds from 

 the centre outwards, or is centrifugal; — just the op- 

 posite of the indeterminate mode, or that where all 

 the flower-buds are axillary. If flowering branches 

 appear from the axils below, the lower ones are the 

 later, so that the order of blossoming- continues centrif- 

 ugal or descending (which is the same thing), as in Fig. 166, mak- 

 ing a sort of reversed raceme ; — a kind of cluster which is to the 

 true raceme just what the flat cyme is to the corymb. 



217. Wherever there are bracts or leaves, buds may be produced 

 from their axils and appear as flowers. Fig. 165 represents the 

 case where the branches, 5 6, of Fig. 164, each with a pair of small 



FIG. J63 a. Diagram of an opposite-loaved plant, with a single terminal flower. 164. 

 Bame, with a cyme of throe flowers ; a, the first flower, of the main axis ; 6 i, those of hranchea. 

 165. Same, with flowers of the third order, c c. 166. Same, with flowers only of the second 

 order from all the axils ; tlie central or uppermost opening first, and so on downwards. 



