THE ANTHODIUM 203 



Compound Inflorescences. — Before proceeding to consider certain 

 special forms and modifications of the inflorescences above defined, 

 it should be remarked that most of the forms may be compound. By 

 this we mean that the cluster is made up of a number of branches whose 

 order of development is the same as that of the elements of which they 

 are composed. That is, the raceme may possess a number of branches, 

 each of which is a smaller or secondary raceme, or if not a raceme, at 

 least a small inflorescence of the ascending or centripetal form. Similarly, 

 an umbel may be made up of branches, each of which is a smaller umbel, 

 the Umbellule. A cyme will be made up of cymules, and so on. A 

 Panicle is a compound raceme which assumes the form of a pyramid. 

 Any form of inflorescence not a true panicle, but assuming the shape 

 of one, is styled Paniculate. 



Complex Inflorescences. — Complex forms of inflorescence differ from 

 the compound in that the order of development of the several flowers 

 upon a branch is of a different kind from that of the several branches 

 themselves. For exmaple, the Thyrsus or Thyrse is a paniculate form 

 in which the lowest branch is the first to develop flowers, so that the 

 order of development of the branches is ascending, but within a branch 

 the terminal flower will be the first to develop, so that the order of 

 development of its flowers is descending. In the same way, each 

 branch of an umbel may terminate in a head ; or we may have a fascicle, 

 each branch of which is a raceme. 



The Anthodium. — The term Anthodium has already been defined in 

 considering the forms of the fruit, under Multiple or Collective Fruits. 

 The same term is applied to an inflorescence yielding the collective 

 fruit of that name (Fig. 587) . It is in reality nothing more than a head 

 closely subtended, surrounded or enclosed by an involucre (a). The 

 anthodium is characteristic of the great family Compositae, and is of so 

 much importance in classification that its modifications call for special 

 attention. The involucre should be studied as to whether it is single, 

 double, or multiple — that is, whether it consists of one, two, or more 

 circles of scales; as to whether these are equal in length or whether the 

 outer or inner are successively shorter; whether they are entirely free 

 and distinct, or adnate by their bases or connate by their margins; as 

 to whether they are appressed, or with more or less of their apical 

 portions recurved or spreading; especially as to the general form of 

 the involucre as a whole, the terms used being the same as those pre- 

 viously applied to the perigone, and as to the characters of the individual 

 scales, these being practically the same as those which have already been 

 considered in connection with the leaves. The body consisting of the 



