THE PRINCIPLE OF AREANGEMENT. 



43 



St. J>et. 



the flower, through which nourishment is withdrawn at 

 certain places to produce hypertrophy elsewhere. Thus the 

 sepaline cord, instead of bearing an anther in Priviula, bifur- 

 cates at the angle, and each branch proceeds up the margin 

 of a lobe of the corolla, and aids in nourishing the latter. 



As a converse instance of the sepaline cord undertaking 

 a considerable amount of work, may be mentioned Campanula 

 medmm. In this plant the 5-lobed fibro-vascular cylinder 

 of the pedicel sends off five cords 

 intended for the calyx (Fig. 8, sep.} ; 

 but, befoi'e reaching the base of the 

 superior sepal, it sends off an inner- 

 most and lowest cord to become the 

 dorsal one of the carpel (d. car.), 

 which, in this flower, is thus super- 

 posed to a sepal. It also sends off 

 two, right and left, one for each 

 petal alternating with it (pet.) ; so 

 that each jietal receives two cords, 

 one from each adjacent sepal, — a 

 most unusual condition of things, 

 for petals have almost invariably 

 their own cords issuing' frora the 



Jiet. 





pedicel. Lastly, the same sepaline Fig. S— Vertical and transverse sec 

 ^ . tions of the wall of the inferior 



cord provides that of the stamen ovary of campanula medium 



(after Van Tieghem). 



{St.) superposed to it. In this 



flower, therefore, we can understand why there is no petal- 



ine whorl of stamens ; simply because the corolla does not 



possess its own proper fibro-vascular cords to give rise to 



them. 



On the other hand, in the Malvaceoi after the axis has 

 supplied cords for the sepals, others furnish those of the 

 corolla; these latter, however, by radial division form two 



