■f 





■- V 



Is 



I 



V 



J ■ 



A revision of Ihc genus Mitella efc. 



389 







4 



T 



J 



J* 

 n i" 



1^ 



. 





Province of Wakasa: 



near Kumagawa 



(K. Tsuzi, April <0, 1901). 

 Said to be a rare species, and to differ from M.japoiiica by the smaller 

 and denser tlowers, 3-fid petals, semi-glabrous leaves, glabrous petioles and 

 sterile bracts upon the scape. Not seen by us. 



Part. in. Relationship and Geographical Distribution. 



The accompanying diagram (fig. 9), seeks to show in a graphic way the 

 relationship of the sections and species to each other and the course of evo- 

 lution in the genus. Where 1 and 5-stamened species occur in a group 

 of clearly related species like Mitdla^ the inevitable conclusion is that the 

 forms with 1 stamens represent the older types and that those with 



I 





4 



. "■ l' 



r- _ 



i 



r JH 



^.' 



1- 



ir. 



t 



h 



Fig. 

 and 



1. 



Sepals in the Sect. Eumitella, showing venation, position of petals, stamens 

 disk, a M. rlinUdln L ni siintirnnpfnla. a and d M. staurovctala var. stenopelala, 



X<o. 



e and f M. irifida, g M. trifida var. violacea, h M. diversifolia. 



5 stamens have been derived from them through reduction of one or 

 the other of the two cycles of stamens. On this hypothesis, therefore, 

 both M. diphylla and M. nuda are older types than the other species and 

 form the starting points from which the others have evolved. These two 

 parent forms show certain close similarities and also some very important 



figu 



For 



the sake of comparing these structures to the best advantage, drawings 

 f>f the different organs of the flower of all the species except one, have 

 been made and arranged in the sequence that we conceive the order of 

 progression to have taken place. In this scheme the odd numbers of 

 figures represent one series or section. The even numbers the other series 

 or section. 



/ 



n 

 '.P, 



