458 : BOTANICAL GAZETTE [DECEMBER 
admit that it is easy to acquire the tendency to give specific 
names to forms which are of such small taxonomic importance 
that the student may be confused rather than enlightened by the 
subdivision. The remarks in this paragraph represent Asa 
Gray’s later conviction, a position which he once summed up to 
me, with his characteristic forcefulness, in the remark that 
‘species are judgments.” I remember his saying to me, in 
effect, that he should consider the Atlantic Ocean to be a good 
distinguishing mark between certain species; that is, that forms 
which would scarcely be considered to be specifically distinct 
when occupying the same or coterminous areas might properly 
be called species if they were separated distinctly by great nat- 
ural barriers. I am quite sure that he looked upon very similar 
forms in very unlike geographical regions as tending towards 
greater differentiation, and whenever it was possible, in perspic- 
uous treatment, to draw fairly good characters of separation 
between them he thought that it was expedient to do so. In 
other words, Gray would not make quantitative characters 
supreme in his designation of species. 
I would not for a moment make it a test of a species that 
there should be no intergradient forms. If the intermediate 
forms are so few that they do not seriously obscure the mental 
conception of the type, then all interests will be subserved by dis- 
regarding them for purposes of nomenclature. In fact, I should 
expect very few species of plants to be perfectly free from aber- 
rant and entangling forms. The groups of plants are rare 1m 
which one can say that the types are unique. Soil, exposure, 
climate, contest with fellows, and a hundred incidental circum- 
stances leave their impress upon the plant forms.’ 
If the making of species is an expediency, then it follows 
that it is not necessary, or even desirable, that we should search 
for obscure or anatomical characters with which to separate 
them. These characters belong to anatomy, physiology, embry- 
2It would seem that some exception might be made to these remarks in the lucid 
genus Carex, for Britton, in deseribing a new species, was able to find “ crucial proof 
of its distinctness.” Bull. Torr. Bot. Club 22 :220. 
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