STRUCTURE.] UMBEL CAPITULUM GLOMERULE. 321 



compound corymb. The modern corymb must not be con- 

 founded with that of Pliny, which was analogous to our 

 capitulum. 



When the pedicels all proceed from a single point, as in 

 Astrantia, and are of equal length, or corymbose, we have an 

 umbel (fig. 80.). If each of the pedicels bears a single flower, 

 as in Eryngium, the umbel is said to be simple (fig. 79. a) ; 

 but if they divide and bear other umbels, as in Heracleum, 

 the umbel is called compound; and then the assemblage of 

 umbels is called the universal umbel, while each of the secon- 

 dary umbels, or the umbellules, is named a partial umbel. 

 The peduncles which support the partial umbels are named 

 radii. Louis Claude Richard confined the word umbel to the 

 compound form, and named the simple umbel sertulum ; but 

 this was an unnecessary change. 



Suppose the flowers of a simple umbel to be deprived of 

 their pedicels, and to be seated on a receptacle or enlarged 

 axis, and we have a capitulum or flower-head. If this is 

 surrounded by an involucre, the compound flower, as it is 

 inaccurately called by the school of Linnaeus, of Composites, 

 is produced ; which is sometimes named by modern botanists 

 anthodium ; it is also called cephalanthium by Richard, cala- 

 this by Mirbel, calathium by Nees von Esenbeck. The 

 flowers or florets borne by the flower-head in its circumference 

 are usually flat or ligulate, and different from those produced 

 within the circumference. Those in the former station 

 are called florets of the ray ; and those in the latter, florets of 

 the disk. 



If all the flowers are hermaphrodite in the flower-head, it is 

 homogamous; if the outer are neuter, or female, and the inner 

 hermaphrodite, or male, it is heterogamous : if on the same 

 plant some flower-heads are composed entirely of male flowers, 

 and others entirely of female flowers, such a plant is termed 

 by De Candolle heterocephalous. 



The glomerule or glomus is the same to a flower-head as 

 the compound is to the simple umbel ; that is to say, it is a 

 cluster of flower-heads inclosed in a common involucre, as in 

 Echinops. 



All the forms of inflorescence which have been as yet 



VOL. i. Y 



