Chap. IV. OXALIS. 169 



styled. In 1866 Professor Hildebrand proved,* by an 

 examination of the specimens in several herbaria, that 

 20 species are certainly heterostyled and trimorphic, and 

 51 others almost certainly so. He also made some in- 

 teresting observations on living plants belonging to 

 one form alone; for at that time he did not possess 



Fig. u. 



Long-atyled. Mid-styled. Short-styled. 



OXA.UB SPECIOSA (with the petals removed). 



S8S, stigmas. The dotted lines with arrows show which pollen must 

 be carried to the stigmas for legitimate fertilisation. 



the three forms of any living species. During the 

 years 1864 to 1868 I occasionally experimented on 

 Oxalis speciosa, but until now have never found time 

 to publish the results. In 1871 Hildebrand published 

 an admirable paperf in which he shows in the case of 

 two species of Oxalis, that the sexual relations of the 

 three forms are nearly the same as in Lythrum sali- 

 caria. I will now give an abstract of his observa- 

 tions, and afterwards of my own less complete ones. 

 I may premise that in all the species seen by me, the 

 stigmas of the five straight pistils of the long-styled 

 form stand on a level with the anthers of the longest 



* ' Monatsber. der Akad. der forms at p. 42 of his ' Geschlechter- 

 Wias. Berlin,' 1866, pp. 352, 872. Vertheihmg,' &c., 1867. 

 He gives drawings of the three t 'BotZeitung' 1871, pp.416, 432. 



