320 AMENTUM SPIKELET SPADIX CORYMB. [BOOK i. 



piece, either after flowering or ripening the fruit, as in the 

 Hazel, Willow, Poplar, &c., such an inflorescence is called an 

 amentum or catkin (Catulus, lulus, nucamentum, of old writers, 



fig. 82.) 



If a spike consists of flowers destitute of calyx and corolla, 

 the place of which is occupied by bracts, supported by other 

 bracts which enclose no flowers, and when with such a for- 

 mation the rachis, which is flexuose and toothed, does not 

 fall off with the flowers, as in Grasses, each part of the inflo- 

 rescence so arranged is called a spikelet or locusta. 



When the flowers are closely arranged around a fleshy 

 rachis, which is enclosed in the kind of bract called a spathe 

 (see p. 311.), the inflorescence is termed a spadix (fig. 83.) 

 This is chiefly found in the Aral and Palmal alliances. It is 

 frequently terminated, as at fig. 83., by a soft club-shaped 

 mass of cellular substance which extends far beyond the 

 flowers, and is itself entirely naked ; this is an instance of 

 a growing point analogous to what forms the spine of a 

 branch, except that it is soft and blunt, instead of being hard 

 and sharp-pointed. 



The raceme has been said to differ from the spike only in 

 its flowers being pedicellate : to this must be added, that the 

 pedicels are all of nearly equal length ; but in many plants, 

 as the Candytuft (Iberis), the lower pedicels are so long that 

 their flowers are elevated to the same level as that of the 

 uppermost flowers ; a corymb is then formed. This term is 

 frequently used in an adjective sense, to express a similar 

 arrangement of the branches of a plant or of any other 

 kind of inflorescence : thus, in Stevia, the branches are said 

 to be corymbose ; in others, the panicle is said to be corym- 

 bose (fig. 87.) ; and so on. When corymbose branches are 

 very loose and irregular, they have given rise to the term 

 muscarium ; a name formerly used by Tournefort, but not 

 now employed. 



If the expansion of an apparent corymb is centrifugal, 

 instead of centripetal; that is to say, commences at the 

 centre, and not at the circumference, as in Dianthus Carthu- 

 sianorum, we then have the fascicle (fig. 84.) ; a term which 

 may not incorrectly be understood as synonymous with 



