DIALYSIS. Ill 



lierb {Epilobium montanum) in whicti calyx, corolla, and 

 androecium were not only completely dissociated from 

 each other, but were situated, in the one case at the 

 base of the ovary, in the other a short way down it ; in 

 these last two positions they Avere of precisely the same 

 vertical height as in the normal position; the superior 

 ovary had also precisely the same appearance (hairy, 

 etc.) ; these two facts, he thinks, force us to the con- 

 clusion that in the normal case the calyx, etc., have 

 been carried up on to the top of the ovary, for if they 

 enclosed it as an axial or leafy receptacle the hairiness 

 of the ovary should disappear in the abnormal condition. 

 This view is hardly acceptable to the present writer, 

 who considers that fusion of the calyx, etc., with the 

 ovary in the normal case must be admitted, for it is 

 inconceivable that one set of floral leaves could be 

 seated on the tips of another set, and the axial theory 

 is unlikely from comparison with other cases of inferior 

 ovaries (see above). Moreover, it is conceivable that 

 the superior ovary and short hypogynous calyx, etc., 

 of the abnormal flower could arise congenitally in 

 those positions with all their previous characters intact, 

 as these characters constitute a useful adaptation to 

 the needs of the plant and the less advantageous 

 intervening stages would naturally be omitted. 



In a flower of the "geranium" {Pelargonium zonale) 

 the spur of the posterior sepal was dissociated from 

 the pedicel, with which it is normally fused, for a 

 distance of several millimetres ; this is a reversionary 

 tendency ; for in its near ally Tropasolum this spur is 

 normally quite free. 



(2) Corolla. 



There are a great many plants which exhibit either 

 partial or complete dialysis of their gamopetalous 

 corolla. Only two or three instances need be given. 

 One of the best-known is that of Gamjjcmmla in which 

 the flower bears five perfectly free outspread petals 



