174 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



THE BRITISH PANSIES. 

 By Eric Drabble, D.Sc, F.L.S. 



[Read April 20, 1909.] 



A species may perhaps be best defined for general working purposes as 

 "the unit of classification " : that is to say, it consists of an assemblage 

 of plants, incapable of being further subdivided into segregates, which 

 breed " true " and show characters sufficiently constant to enable them to 

 stand as distinct forms. 



The pre-Linnean conception of a species seems to have been rather 

 what we now call a "genus " — a group of plants showing many features 

 in common — for example, the clovers — but readily further separated with 

 a little care into truly distinct forms with constant characters. Linnaeus 

 set himself to deal with a heterogeneous and somewhat chaotic material, 

 out of which it was his ambition to evolve some sort of order. Consider- 

 ing the nature of the material upon which he had to work one cannot 

 but wonder and admire at the magnitude and accuracy of his results. 

 That in many instances he grouped two or even several forms together 

 under one name is no cause for surprise — indeed, he himself was quite 

 aware of this fact ; what must occasion surprise is that in the vast 

 majority of cases his conclusions have stood the test of time, and this in 

 spite of the careful scrutiny of specialists in the various groups. That 

 Linnaeus did not stay to split some of the more puzzling and critical 

 groups into their ultimate species was due to the fact that he desired to 

 cover the whole Vegetable Kingdom in his researches, and hence he left 

 such groups to the discriminating examination of those of his successors 

 who should devote their attention to small subdivisions of the Plant 

 Kingdom. 



Thus it happens that in several cases the " Linnean Species " falls 

 but little short of being a genus, including several closely allied species. 

 This is very noticeably the case in Viola tricolor. 



A great reproach to which systematists have laid themselves open 

 since the time of Linnaeus — particularly his earlier followers — is that 

 they have followed too slavishly in his footsteps and have hesitated to 

 question his conclusions by experiment. This charge, however, must not 

 be brought against all systematists even of the past. Alexis Jordan in 

 1846 (" Observations sur plusieurs Plantes nouvelles ou critiques de la 

 France," Deuxieme Fragment) very cogently states the case for further 

 examination, and says that in his day systematists were very much 

 inclined to assume that the last word on the question of species had been 

 pronounced by Linnaeus. But as for himself, he tells us, he refused to 

 adhere blindly to the old traditions, and as the result of his work we are 

 now in a position in several genera to realize clearly the composite nature 

 of the " Linnean Species." His good work was carried on by Boreau and 

 ethers, and is now being continued by many workers at home and abroad. 



