143 



peated in their descendants ; and that the distinctive characters of 

 one species are never assumed by the progeny of another species. 



It must be confessed, however, that there is much difficulty in re- 

 conciUng this belief with the familiar fact, that in many genera the 

 number and distinctions of the supposed species seem to depend 

 pretty much upon the fancy of the botanists who describe them. 

 Thus, in the genera Salix, Rosa, Rubus, Mentha, Viola, Festuca, Poa, 

 Saxifraga, Cerastium, Hieracium, Polygonum, Myosotis and others, 

 the number of species may be held optional with botanical authors. 

 Such a remark may startle some of our great " species-botanists ; " 

 and yet, in the short table below, we have something very like a proof 

 of its correctness. The table is intended to show the number of in- 

 digenous species in some of these genera, varying according to the 

 author who describes and catalogues them. 



Hudson (1791), 



Smith (1824—8), 



Lindley (1835), 



Hooker (1842), 



Babington (1843), 



London Catalogue (1844), 



Some few of the species were first discovered in this country during 

 the present century ; but these novelties will go only a short way to- 

 wards making up the wide differences between Hudson and Smith. 

 The grand cause of the varying numbers arises from discordant views 

 about species and varieties ; those forms which by one author are 

 described for distinct species, by another are included together as 

 varieties only of the same single species. I select the genera named 

 above, as examples of uncertainty in numbers, because their described 

 species are numerous. Equivalent differences will appear in other 

 genera, where the species are few. Thus, Hudson's solitary (or, du- 

 biously, two) species of Myosotis has now expanded into eight. His 

 six species of Viola have been increased to ten, although they are now 

 again reduced to six or seven. From his two species of Betula we 

 have seen four made, and a fifth is now threatened under the significant 

 sentance of " probably a distinct species." So, on we might go, with 

 the species of many other genera. It will be borne in mind here, that 

 the plants of Britain have been long and carefully studied by many 

 able botanists ; and it would hence seem impossible for such differen- 



