THE INFLORESCENCE. 



121 



When the floral axis of a raceme is so shortened, and the 

 peduncles of the lower flowers are so elongated, as to elevate 

 them to the same level as the upper flowers, a corymb is 

 formed, as in Achillea millefolium. If the floral axis of a 

 raceme be suppressed altogether, so that the peduncles all 

 start from the same point, we have an umbel, (Fig. 26.) 



Fig. 26. Fig. 27. 



b c 



Tig. 28. Diagrams of a corymb b, and of an umbel c. 



If the secondary floral axis of a raceme gives rise to tertiary 

 ones, the raceme is branching, and forms a panicle, (Fig. 27.) 

 The panicle ordinarily assumes a pyramidal form, that is to say, 

 the floral axes become shorter in proportion as they approach the 

 summit. If on the contrary, the floral axes of the middle part 

 are the longest, the inflorescence takes a more or less ovoid 

 form, and is denominated a thyrsus, as in the lilac. 



The definite and determinate inflorescence. The lowest 

 developments of this form of inflorescence, is that in which a 

 single floral axis is terminated by a solitary flower, of which 

 the Anemone nemorosa furnishes a good example. When such 

 an inflorescence branches, the branches do not grow in an 



11* 



