150 



ANTHOTAXY, OB INFLORESCENCE. 



AMENT or CATKIN. This is merely that kind of spike with 

 scaly bracts borne by the Birch (Fig. 289), Poplar, Willow, and, 

 as to one sort of flowers, by the Oak, Walnut, and Hickory, 

 which are accordingly called amentaceous trees. Catkins usually 

 fall off in one piece, after flowering or fruiting. All true catkins 

 are unisexual. 



277. Any of these forms of simple inflorescence may be com- 

 pounded. Racemes may themselves b'e disposed in racemes, spikes 

 in spikes (as in Triticum) , heads 

 be aggregated in heads, umbels in 

 umbels, corymbs may be corvm- 

 bosely compound, &c. ; forming 

 compound racemes, spikes, utnbels, 

 and the like, the terminology of 

 which is eas} T . The most usual 

 case of truly homomorphous com- 

 pounding is that of umbels ; the 

 inflorescence of much the larger part of Umbelliferae being in 

 compound umbels, as in Fig. 290". There is then the general 

 umbel, the rays of which become peduncles to 

 the partial umbels, and the rays of the latter 

 are pedicels. Umbella and Umbellnlee desig- 

 nate in Latin terminology the general and its 

 partial umbels. Umbellets (coined by the late 

 Dr. Darlington) may well replace the latter 

 as the English diminutive. But umbels are 

 sometimes racemosely arranged, as in Aralia 

 spinosa, heads may be arranged in spikes, 

 and so on. 



278. A Panicle, of the simple and normal 

 sort (as illustrated in Fig. 291), is produced 

 when a raceme becomes irregularl} T compound 

 by some (usually the lower) of its pedicels 

 developing into peduncles carrying several 

 flowers, or more than one, or branching again 

 and again in the same order. But in com- 

 pound clusters generally the secondary and 

 tertiary ramifications are apt to differ in type 

 as well as in particular mode, giving rise to 

 heteromorphous or mixed inflorescence. (288.) 

 As Linnaeus defined the term, and as it has generally been em- 

 ployed in botanical descriptions, the panicle is a general term 



FIG. 290 Compound umbel of Caraway. 291. A simple panicle. 



