218 THE INFLORESCENCE. 



what forms their footstalks or pedicels, and these are nearly equal in 

 length, a raceme-like inflorescence is produced, as in Fig. 330 ; or 

 when the flo^vers have scarcely any pedicels, the spike is imitated. 

 These are distinguished from the true raceme and 

 spike, however, by the reverse order of development 

 of the blossoms ; the terminal one opening earliest, and 

 the others expanding in succession from above down- 

 wards ; while the blossoming of the raceme proceeds 

 from below upwards. Or when, by the elongation of 

 the lower secondary axes, a corymb is imitated, the 

 flowers are found to expand in succession from the 

 centre of each ramification, beginning in the centre of 

 the cluster, while the contrary occurs in the corymb. 

 That is, while the order in indeterminate inflorescence 

 is centrijietal (387), that of the determinate mode is 

 centrifugal. When the determinate inflorescence as- 

 sumes the flatfish or convex form, which it more com- 

 monly does, it has a distinctive name, viz. : — 



403. The Cyme. This is a flat-topped, rounded or expanded in- 

 florescence, whether simple or compound, of the determinate class ; 

 of which those of the Laurustinus, Elder, Dogwood, and Hydrangea 

 (Fig. 420) are fully developed and characteristic examples. In com- 

 pound and compact cymes, such as those of the Laurustinus, Dogwood, 

 &c., the leaves or bracts are usually minute, rudimentary, or abor- 

 tive, and all the numerous flower-buds of the cluster are fully formed 

 before any of them expand ; and the blossoming then runs through 

 the whole cluster in a short time, commencing in the centre of the 

 cyme, and then in the centre of each of its branches, and thence pro- 

 ceeding centrifugally. But in the duckweeds (Fig. 331), in Hy- 

 pericum, and many similar plants, the successive production of the 

 branches and the evolution of the flowers, beginning with that which 

 arrests the growth of the primary axis, go on gi*adually through the 

 whole summer, until the powers of the plant are exhausted, or until 

 all the branclilets or peduncles are reduced to single internodes, or 

 pedicels destitute of leaves, bracts, or bractlets, when no fui-ther de- 

 velopment can take place. Such cases enable us to study the deter- 

 minate inflorescence to advantage, and to follow the successiv^e steps 

 of the ramification by direct observation. 



404. A Cymule {Cymuld) is a diminutive cyme, or a branch or 

 cluster of a compound cyme. 



FIG. 330. Definite inflorescence imitating a raceme. 



