REJUVENESCENCE IN NATURE. 77 



also in Hypericum calycinum, in which the sepals of the 

 solitary terminal flowers are twice or four times as long, 

 and three to four times as broad as the preceding hyp- 

 sophyllary-leaves ; finally, most distinctly in Chelidonium 

 majus, in which the sepals are about three lines long, 

 while the two to three pairs of preceding hypsophyllary- 

 leaves, from the axils of which the lateral flowers of the 

 corymb arise, attain scarcely half a line. In the calyx 

 itself the metamorphosis usually keeps at the same stage, 

 so that at least no remarkable difference occurs among 

 the sepals ; yet the cases are not rare in which an evident 

 gradation occurs within the calyx itself, an increase of 

 length corresponding to the succession of the sepals ; as, 

 for instance, in the quinate calyx of Hypericum caly- 

 cinum, imbricated in the | arrangement, the inner two 

 sepals of which are almost twice as long as the outer 

 two, the third being of intermediate length. The con- 

 ditions are similar in Polygala, where the innermost two 

 sepals are not merely many times longer than the outer 

 three, but already exhibit the petaloid colour, forming 

 what are called the wings of the flower.* In Oxyria 

 and the female flowers of Urtica we find a four-leaved 

 calyx, the outer two sepals of which are shorter than the 

 inner two; in Rumex a six-leaved, with three outer 

 shorter, and three inner longer. Berberis has a double 

 ternate, Mahonia and Podophyllum a triple ternate, and 

 Epimedium, a triple binate calyx ; in all these the inner 

 whorls are formed of longer sepals than the outer. 

 Lastly, in the Cactese, as also in Co.lycanthus, the gradual 

 increase of length is exhibited most remarkably with an 

 acyclic structure of the calyx. 



The length of the leaf within the flower attains its 

 maximum in the corolla. It is scarcely necessary to illus- 

 trate, by examples, the proportionate lengths of the 

 corolla and calyx ; and the assertion that the petals are 

 longer than the sepals in the majority of plants possessing 



* The same occurs in ~Di.}>l<>rociirpii*. 



