THE PRINCIPLE OF ARRANGEMENT. 



43 



St. J>et. 



the flower, througli which nourishment is withdraw^n at 

 certain places to produce hypertrophy elsewhere. Thus the 

 .sepaline cord, instead of bearing an anther in Primula, 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 Camjoanula 

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

 of the pedicel sends off five cords 

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

 but, before 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 petal receives tw^o cords, 

 one from each adjacent sepal, — a 

 most unusual condition of things, 

 for petals have almost invariably 

 their own cords issuing from the 



pedicel. Lastly, the same sepaline Fip. S.— A^rtical amUransverse pec- 



^ "^ ' ■■■ tions of tlie wall ot the inferior 



cord provides that of the stamen ovary of Campanulu medium 



•^ , . (after Van Ticghem). 



(st.) superposed to it. In this 



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



iue 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 Malvacecv after the axis has 

 supplied cords for the sepals, others furnish those of the 

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



<13'"'" 



