Nov. 1898.] BOTANICAL SOCIETY OF EUINBUEGH 125 



De Candolle writes : " We unite as species all those 

 individuals that have so close a resemblance as to allow 

 of our supposing that they have descended from a single 

 being, or a single pair." 



Buffon writes : " A species is a constant succession of 

 individuals, similar to, and capable of reproducing, each 

 other." 



Cuvier writes : " A species is a succession of individuals 

 which reproduces and perpetuates itself." 



Sir Charles Lyall rejected Lamarck's theory of trans- 

 mutation of species, on the ground that if species were, as 

 Lamarck said, descended from a common ancestor, they 

 would be able to breed together, which was not the case. 



Darwin says : " There is no well-marked distinction 

 between races of domestic animals and so-called true 

 species, except that the former are fertile when crossed "; 

 and in "The Origin of Species," page 236, he says: "The 

 fertility of varieties is, with reference to my theory, of 

 equal importance with the sterility of species, for it seems 

 to make a broad and clear distinction between varieties 

 and species." 



It is, I think, clear that as long as we quote De Candolle, 

 Buffon, Cuvier, and Darwin as authorities, we ought to 

 use the words they employ in the sense they intended, and 

 not in any oth^r sense. 



This especially applies to the word species. In reading 

 and quoting these classic authors, we must understand by 

 species what they understood. 



In sexual plants — phanerogams, ferns, mosses, etc. — we 

 can say positively what is a species, and what is not, 

 because we can ascertain whether the pollen of one in- 

 dividual will fertilise the seed of another. 



On the other hand, in the group of fungi, called 

 Basidiospores, we can only have provisional species. All 

 we know is, that the spores of Armillaria mdleus reproduce 

 the plant A. mdleus ; but \ve do not know whether it is a 

 species or not. It may only be a permanent variety. 



The distinction is not a mere verbal one, but most 

 important, for since Darwin's book was called " The Origin 

 of Species," and since we cannot say of any Basidiospore 

 whether it is a species or not in Darwin's sense, all 



