454 LETTEES TO DAEWIN, 1843-1859 



a great deal on amount of variability in great and small 

 genera, and find it exceedingly difficult to explain logically 

 the practical reasons there are against Botanists making 

 varieties of well marked species, i.e. of small genera. Many 

 of the small genera still kept up would never have been made 

 at all, had the whole of the Natural Order as now known been 

 known when those genera were made. E.G., in Europe 

 we have, say 3 very different members of a large unknown 

 Asiatic group of plants, certainly 100 species : of these 3 

 as many genera are made in Europe : but after getting all 

 the 100 Asiatic species, though these show that the said 3 

 genera are naught, we do not therefore cancel them, but in 

 9 cases out of 10 we group the Asiatic species as best we can 

 under the 3 European genera. A thousand unphilosophical 

 reasons occur, of considerable (present practical) weight to 

 keep up the said old genera. 



We must never forget that Systematists have two very 

 different ends to meet : 1. To provide a ready nomenclature 

 without which the science cannot advance and which we 

 change as little as possible and further use every means 

 to avoid even a necessary change so important is it for 

 all to get up the nomenclature, and so bulky and complicated 

 is this nomenclature. 2. To arrange the members of the 

 Vegetable Kingdom scientifically, which is only done for 

 the sake of scientific followers. Now we repeatedly find 

 that to express our views scientifically we must break up 

 the whole nomenclature, and rather than do this excessively, 

 we confine ourselves to stating our views without acting 

 upon them. In no respect do we sacrifice more to the 

 utilitarian purpose of nomenclature, than in keeping up 

 small bad genera. 



Practically no one (except a few of us) hesitates to remove 

 a very distinct species of an old genus, especially if its 

 characters are constant and it is an invariable plant, and to 

 make of it a new genus, just because it is more unlike its 

 20 neighbours than they are unlike one another. The 

 probabilities in this case are that the 20 are varieties of 

 8 or 10, and being variable have varieties made of them- 

 selves, whilst the one constant plant goes to a new genus, 

 and is a small genus with no varieties. 



Again, practically very few do up an old genus of one 



