DEFINITE INFLORESCENCE. 



159 



giving rise to the peculiar inflorescence of Dorstenia (fig. 245), or to 

 that of the Fig (fig. 246), where/ indicates the flowers placed on the 

 inner surface of the receptacle, and provided with bracteoles. This 

 inflorescence has been called Hypanthodium (tiro, under, and ay do;, a 

 flower). 



337. On reviewing these different kinds of inflorescence, it will be 

 observed that the elongation or shortening of the axis, and the presence 

 or absence of stalks to the flowers, determine the different varieties. 

 Thus, a spike is a raceme in which the flowers are not stalked, the 

 umbel a raceme in which the primary axis is shortened, the capitulum 

 or head a spike in which the same shortening has taken place. 



338. Definite inflorescence. The simplest form of this inflorescence 

 is seen in Anemone nemorosa (fig. 247), or in Gentiana acaulis (Gen- 

 tianella) where the axis terminates in a single flower; and if other 

 flowers are produced, they arise from the leaves below the first-formed 

 flower. When numerous flowers are produced, and the axes are much 

 shortened, it is sometimes difficult to understand this mode of in- 

 florescence. It may be distinctly traced, however, in plants with 

 opposite leaves, in which the different axes are clearly developed. In 

 fig. 248 is represented the flowering branch of Erythrasa Centaurium. 

 Here the primary axis, ', ends in a flower, /", which has passed 

 into the state of fruit. At its base two leaves are produced, each 

 of which is capable of developing buds. In the Gentiana acaulis 



Fig. 2-14. Inflorescence of Dipsacus sylvestris. Glomerulns, or head of flowers, each of 

 which is separated by long pointed bracts. The flowers are evolved in a centripetal manner. 

 e i, The first expanded, followed by those at e m, while those at the apex, e s, are in bud. 



Fig. 245. Inflorescence of Dorstenia Contrayerva, consisting of a broad slightly concave 

 receptacle, r, on which numerous male and female flowers, f, are placed. 



Fig. 246. Inflorescence of Fig (Fiats Carica). showing the hofiow receptacle, r, or peduncle, 

 which forms the fruit covered with flowers, /, of various kinds. 



