DIALYSIS. 109 



mentions the genera Primula, Symphytum, Gentiana, 

 Gampanula (PI. XXXIX, fig. 1), and others as showing 

 it. In each of these the normal flower has also a 

 gamopetalous corolla. 



Partial dialysis of the calyx has occurred in Primula 

 sinensis; the sepals thus separated were in all cases 

 long-stalked and foliaceous. 



All so-called "inferior ovaries" ai'e here regarded as 

 being enclosed externally by the basal portions of the 

 sepals. In the case of the Umbelliferae the major part 

 of the sepal is used up for this purpose ; in the 

 Rosacese, with completely organized sepals above the 

 " fruit," it would seem, at first sight, more natural, as 

 Celakovsky and others maintain, that the sepals have 

 been displaced into that position through a cupular 

 upgrowth of the axis around the ovary. But, supposing 

 fusion of the sepal with the ovary to have occurred, 

 there is no reason why the upper free portion of the 

 sepal could not have become reorganized into the con- 

 stituent parts of sheath, petiole, and blade. For there 

 are instances in which the same kind of change occurs, 

 viz., where a leaflet of a compound leaf, usually perfectly 

 simple, may assume the complexity of organization of 

 an entire leaf. Grood instances of this are seen in the 

 aphlebia of the tree-fern (Semitelia) and in the leaflets 

 of the laciniate varieties of the elder {Samhucus nigra) . 



In abnormal cases the calyx tends to become dis- 

 sociated from the ovary, and at the same time the 

 latter often becomes superior. Such free sepals have 

 been observed in Umbellifer^ (PI. XXXIX, fig. 2). In 

 the proliferated pears, described on an earlier page, the 

 bases of the sepals in one or more of the extra pears 

 formed by proliferation tend to become separated out 

 and individualized ; the outline of each is distinct and 

 clear (see PI. XXVIII, fig. 2) ; this is not the case 

 with the normal pear at all. Planchon describes an 

 interesting phenomenon in the quince (Cydonia) which 

 was surmounted by five more or less foliaceous sepals, 

 the surface of the fruit having five distinct ridges, each 



