THE PRINCIPLE OF ARRANGEMENT. 



43 



St. J>e&. 



the flower, througli which nourishment is withdrawn at 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 np 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 

 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, 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 petal receives two 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 

 cord provides that of the stamen 

 (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 Malvacece after the axis has 

 supplied cords for the sepals, others furnish those of the 

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



sl:/^ 



^st. 



Fig. 8. — Vertical and transverse sec- 

 tions of the wall of the inferior 

 ovary of Campanula medium 

 (after Van Tieghem). 



