PREFACE. xvii 



monoecious, and like those of /. regia consist of two 

 sets, one being proterandrous and the other proterogy-. 

 nous (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 her- 

 maphrodite, male and female plants. The case is here 

 mentioned because the flowers on the females are small 

 like those on the females in the gyno-dicecious sub-class. 

 In an article in the ' Bull. Torrey Bot. Club,' July, 1871, 

 this Silene is, however, said to be gyno-dicecious. As-' 

 ■paragus officinalis is also polygamous, and the female 

 flowers are about half the size of the male ones; see 

 'Gard. Chron.,' May 35, 1878 ; also Breitenbach, in 'Bot. 

 Zeitung,' 187«, p. 163. 



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

 dicecious plants, or those which exist as hermaphrodite 

 and female individuals; namely, according to Mr. 

 Whitelegge ('Nature,' Oct. 3, 1878, p. 588), Stachys 

 germanica, Ranunculus, acris, repens, and bulbosus. 

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

 Geranium sylvaticum and Dianfhus superbus in this 

 state, and the female flowers of the former were of 

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

 me in a letter. I have received an additional account 

 of Plantago lanceolata being gyno-dicecious in England ; 

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

 of no less than flve 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- 

 dicecious condition has been gained, H. Miiller main- 

 tains by many able arguments (' Kosmos,' 1877, pp. 23, 

 128j and 290) the view which he has propounded; and 

 several botanists think it more probsible than the one 



