INDETERMINATE INFLORESCENCE. 



221 



buds being at once terminated by a single flower. But the lateral 

 flower-stalks may themselves branch, just as ordinary branches 

 give rise to branchlets ; when the inflorescence becomes compound. 

 The modifications produced by a second branching of the inflores- 

 cence are readily understood. If the branches of a raceme are 

 prolonged, and bear other flowers on pedicels similarly arranged, a 

 compound raceme is produced ; or, if the flowers are sessile, a com- 

 pound spike is formed. A corymb, the branches of which are 

 similarly divided, forms a com- 

 pound corymb ; and an umbel, 

 where the branches (often called 

 rays) bear smaller umbels at their 

 apex, is termed a compound um- 

 bel ; examples of which occur 

 in almost all the species of the 

 Family Umbelliferse, which is 

 so named because all its plants 

 bear umbels. For these sec- 

 ondary umbels, a good English 



name has been employed by Dr. Darlington, that of UMBELLETS. 

 Their involucre, when they have any, is distinguished from that of 

 the principal umbel by the name of INVOLUCEL. 



397. It is often necessary to distinguish between the bracts on 

 the branches of the inflorescence, and those at the base of the pri- 

 mary branches ; in which case the former are termed BRACTEOLES, 

 or BRACTLETS ; but there is no real limit, either between bractlets 

 and true bracts, or between bracts and true leaves. 



398. When the inflorescence is compound, it is readily seen that 

 two or more modes of inflorescence may be combined ; the first 

 ramification following one plan, and the subdivision another. The 

 combination is usually expressed by a descriptive phrase, as " spikes 

 racemose, or racemed," " heads corymbose," &c. The combina- 

 tion of the raceme and the corymb or the cyme gives rise to a 

 form of inflorescence which has a technical name, viz. : 



399. The Panicle, This is formed when the secondary axes of a 

 raceme branch in a corymbose manner, as in numerous Grasses 

 (Fig. 238), or those of a corymb divide in the manner of a ra- 

 ceme. And the name is loosely applied to almost any open and 



FIG. 247. Compound umbel (in fruit) of Osmorhiza longistylis : a, the involucre: b, b, in- 

 volucela. 248. A separate flower enlarged, with its subtending bract of the involucel. 



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