LESSON 11.] DETERMINATE INFLORESCENCE. 



81 



210. A Catkin Of Ament is the name given to the scaly sort of spike 

 of the Birch and Alder, the Willow and Poplar, and one sort of 

 flower-clusters of the Oak, Hickory, and the like ; on which ac- 

 count these are called Amentaceous trees. 



211. Sometimes these forms of flower-clusters become compound. 

 For example, the stalks which, in the simple umbel such as has 

 been described (Fig. 159), are the pedicels of single flowers, may/ 

 themselves branch in the same way at the top, and so each become 

 the support of a smaller umbel ; as is the case in the Parsnip, Cara- 

 way, and almost the whole of the great family of what are called 

 Umbelliferous (i. e. umbel-bearing) plants. Here the whole is 

 termed a compound umbel; and the smaller or partial umbels take 

 the name in English of umbellets. The general involucre, at the 

 base of the main umbel, keeps that name ; while that at the base 

 of each umbellet is termed a partial involucre or an involuceL 



212. So a corymb (Fig. 158) with its separate stalks branching 



again, and bearing smaller clusters of the same 

 sort, is a compound corymb; of which the Moun- 

 tain Ash is a good example. A raceme .where 

 what would be the pedicels of single flowers 

 become stalks, along which flowers are disposed 

 on their own pedicels, forms a compound raceme, 

 as in the Goat's-beard and the False Spikenard. 

 But when what would have been a raceme or a 

 corymb branches irregularly into an open and 

 more or less compound flower-cluster, we have 

 what is called 



213. A Panicle (Fig. 163); as in the Oat and 

 in most common Grasses. Such a raceme as that 

 of the diagram, Fig. 156, would be changed into 

 a panicle like Fig, 163, by the production of a 

 flower from the axil of each of the bractlets If. 



214. A ThjTSUS is a compact panicle of a pyram- 

 idal or oblong shape ; such as a bunch of grapes, 

 or the cluster of the Lilac or Horsechestnut. 



215. Determinate Inflorescence is that in which the flowers are from 

 terminal buds. The simplest case is where a stem bears a soli- 

 tary, terminal flower, as in Fig. 163 a . This stops the growth of 



8 & F 5 



FIG. 1C3. A Panicle 



