INFLOEESCBNCE. 



fig. 135). In the Stock and many allied plants, the inflorescence is at first a corymb, 

 but changes to a raceme as the primary axis lengthens. 



3. In the umbel {umbella) the secondary axes are equal in length, and starting from 



the same point, flower at the same 



height, diverging like the rays of a 



parasol; it is a raceme of which 



the primary axis is reduced almost 



to a point. The umbel is simple 



{sertulum), Mvhen the secondary axes 



flower {Cherry, fig. 186) ; it is com- 

 pound, when these bear umbellately 



arranged tertiary axes, called 



partial umbels [umbellulw. Fennel, 



fig. 137; Carrot, fig. 138; Fool's 



Parsley, fig. 139). 



The bracts, which in most racemes spring, like the pedicels, from different heights, 

 in many umbelliferous plants rise on a level, like the secondary and tertiary axes, 

 and form a whorl. The name 

 invohicre [involucrum) is given to 

 the bracts at the base of the umbel 



8. Carrot. Tlmbels with involucre ; 

 umbellulse with inTolucels. 



139. .ffithusa. 

 Umbel without involucre ; 

 umbellulje with involucela. 



f\ 



140. Plantain. 141. Vervain. 142. Wheat. 



Simple spike. Simple spike. Compound spike. 



143. Oat. Panicle of spikeleta. 



{Ca/rrot, fig, 138), and that of involuCel or partial involucre {involucellum) to the 



»3 



