MIXED INFLORESCENCE. 



187 



florets, or small flowers to the receptacle, open centripetally, those at the 

 circumference first. So also in Labiatae, such as dead-nettle (Lamium), 

 the different whorls of inflorescence are developed centripetally, while 

 the florets of the verticUlaster are centrifugal. Sometimes this mixed 

 character presents diflBculties in such cases as Labiatse, where the 

 leaves, in place of retaining their ordinary form, become bracts, and 

 thus might lead to the supposition of all being a single inflorescence. 

 In such cases, the cymes are described as spiked, ^racemose, or panicled, 

 according to circumstances. In Saxifraga umbrosa (London pride), 

 and in the horse-chestnut, we meet with a raceme of scorpioid cymes ; 

 in sea-pink, a capitulum of contracted scorpioid cymes (often called a 

 glomerulus) ; in Laurustinus a compound umbel of dichotomous cymes. 

 In concluding this subject of inflorescence, the following diagrams 

 m^y serve to lEustrate the different types of inflorescence : — 



Pig. 279. 



Fig. 277 shows an indefinite inflorescence — i.e. one in which all 

 the flowers belong to the same axis. Here we have a single elongated 

 axis, giving off laterally a floret (1), which expands first ; beyond this 

 the axis elongates and gives off another floret (2), which expands 

 after the first one — and so on were the axis elongated farther. Thus, 

 in this case, the flowers develop from below upwards, and if we were 



Fig. 27T shows Indeflnite inflorescence, in -whioli the lower floret (1) expands first, and 

 then the upper floret (2). Fig. 278 shows definite inflorescence, where the terminal floret 

 (1) opens first, and then the lower floret (2). Fig. 279 shows definite inflorescence with 

 numerous floral axes. The first floral axis hears a flower (I), which opens first ; from this 

 axis come off two floral axes (2 2), the flowers of which expand next ; then each of these 

 gives off two floral axes (3 3, 8 3), which expand third in order, and so on. 



