THE NORTH AMERICAN SPECIES OF AQUILEGIA. 
By Epwin BuakeE Payson. 
INTRODUCTION. 
Doctor Gray once said: ‘‘Species are but judgments—judgments 
of variable value, and often very fallible judgments.” No one who 
has ever studied plants in the field, in the garden, or in the herba- 
rium will question the truth of this remark. Species are, indeed, 
judgments, and not only that, they are matters of convenience. It 
very often happens that species merge into one another almost 
imperceptibly, and for this reason it is often hard to decide how to 
classify an intermediate form. Yet the persistence of these inter- 
mediate forms furnishes no reason why the extremes should not be 
considered separate species. In order to speak accurately, and in 
order to make systematic botany of real value to science, distinc- 
tions must be critical and nice. The practice of grouping a mass of 
distinguishable and distinct things under a single name deserves no 
sympathy; but, on the other hand, the habit of giving a specific 
name to every slight variation is equally bad. The variability of 
the species is, of course, much more marked in some genera than in 
others. Aquilegia is a genus of the former class. 
Different characters have different relative values for purposes of 
classification, and these characters differ in different genera; what 
would be considered specific in one group is no criterion in another. - 
In Aquilegia characters which are of the utmost importance in 
many other genera are practically of no value. The leaflets, for 
instance, are extremely variable in size and shape and, except in a 
very general way, are of no diagnostic value. Whether the leaves 
are twice ternate or thrice ternate, on the other hand, seems to be 
a criterion of considerable value, although plants of species normally 
having triternateleaves may occasionally develop biternate leaves, and 
very occasionally those with biternate leaves may produce triternate 
ones. In a general way, certainly, this character is very useful. It 
will be in place, also, to notice in this connection that the species of 
the warmer, more arid regions are those having triternate leaves 
with rather small leaflets, while those of cool, moist regions are the 
ones with biternate leaves and large leaflets. Similarly, species of 
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