PREFACE. XVU 



U. States are monoecious, and like those of J. regia 

 consist of two sets, one being proterandrous and the, 

 other proterogynous (Mr. C. G. Pringle, in Bot. Gazette, 

 vol. iv. 1879, p. 237) ; and thus the cross-fertilisation 

 of distinct trees is insured. Mr. Alex. S. Wilson 

 informs me that Silene inflata is polygamous on Ben 

 Lawers, as he found hermaphrodite, male and female 

 plants. The case is here mentioned because the flowers 

 on the females are small Hke those on the females in 

 the gyno-dioecious sub-class. In an article in the Bull. 

 Torrey Bot. Club, July 1871, this Silene is, however, 

 said to be gyno-dioecious. Asparagus offieinaUs is also 

 polygamous, and the female flowers are about half the 

 size of the male ones ; see Gard. Ghron. May 25, 1878 ; 

 also Breitenbach in Bot, Zeitung, 1878, p. 163. 



Several cases can now be added to my list of gyno- 

 dioecious plants, or those which exist as hermaphrodite 

 and female individuals; namely, according to Mr. 

 Whitelegge (Natwe, Oct. 3, 1878, p. 588), Stachys 

 germaniea, Banimculus, acris, repens and bulbosus. 

 H. MiiUer found on the Alps (Nature, 1878, p. 516) 

 Gera/niwm sylvaticmn and DioMthus superhus in this 

 state, and the female flowers of the former were of 

 small size. So it is with Salvia pratensie, as he informs 

 me in a letter. I have received an additional account 

 oiPlantago lanceolata being gyno-dioecious in England ; 

 and Dr. F. Ludwig of Greiz has sent me a description 

 of no less than five forms of this plant which graduate 

 into one another ; the intermediate forms being com- 

 paratively rare, whilst the hermaphrodite form is the 

 commonest. With respect to the steps by which a 

 gyno-dioecious condition has been gained, H. Miiller 

 maintains by many able arguments (Kosmos, 1877, 

 pp. 23, 128 and 290) the view which he has propounded ; 

 and several botanists think it more probable than the 



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