PRESIDENTIAL ADDRESS. 659 
systematic contributions, and in all descriptive work undertaken on behalf 
of economic research, the better because the more useful results are supplied 
by workers in whom capacity and attitude combine to induce the recognition 
rather than the reduction of easily characterised forms. 
In the present state of our knowledge uniformity in the delimitation of 
what are termed ‘ species ’ is unattainable. We are in no danger of forgetting 
this fact ; what we do sometimes overlook is that, circumstanced as we are, such 
uniformity is undesirable. The wish to be consistent is laudable ; when it 
becomes a craving it blunts the sense of proportion and may lead to verbal 
_agreement being mistaken for actual uniformity. The thoughtful syste- 
matist, when he considers this question without prepossession, finds that 
forms which in one collocation need only be accorded a subordinate position 
must, under other conditions, receive separate recognition. 
The normal effect on specific limitation of the causes that militate against 
uniformity is easily understood, and the resulting discrepancies can be 
allowed for in statistical statements. There are, however, cases where the 
capacity for appreciating differential characters or points of agreement is so 
highly developed as to obscure or even inhibit the complimentary capacity. 
The effects are then ultra-normal ; nicety of discrimination exceeds the ‘ fine 
cutting ’ allowable in floristic work ; aggregation exceeds the limits useful in 
monography. No common measure is applicable to the results, and the 
ordinary systematist, who has definite and practical objects in view, expresses 
his impatient disapproval in unmistakable terms. The work of those 
addicted to one habit he characterises as ‘hair-splitting’; that of those who 
adopt the other he speaks of as ‘lumping.’ The industry displayed in 
elaborating monographs which attribute a thousand species to genera wherein 
the normal systematist can hardly find a score must often be effort misplaced. 
The same remark applies to the excessive aggregation that substitutes for a 
series of quite intelligible forms an intricate hierarchy of sub-species, 
varieties, sub-varieties, and races. Orgies of reduction are moreover open to 
an objection from which debauches of differentiation are free. Discrimina- 
tion can only be effected as the result of study ; the finer the discrimination, 
the closer this study must be. Reduction offers fatal facilities for slovenly 
work, over which it throws the cloak of an erudition that may be specious. 
When dealing with excessive differentiation the normal systematist is on solid 
ground ; when following extreme reduction he may become entangled in a 
morass. Yet workers of both classes only exhibit the defects, for ordinary 
purposes, of striking merits, and there are occasions when the results that 
each obtains may be of value to science. 
Its mnemonic quality renders taxonomic work practically useful. Its 
application in economic research does the same for specific determination. 
Economic workers are chiefly interested in useful or harmful species ; to others 
they would be indifferent were these not liable to be mistaken for such as are 
of direct interest. The identification of economic species and their dis- 
crimination from neutral allies is not always simple, because species that are 
useful or noxious are often those least perfectly known. The qualities that 
render them important frequently first attract attention; these may be 
associated with particular organs or tissues, and samples of these parts alone 
may be available. Ordinarily, when material is incomplete, critical examina- 
tion has to be postponed. In economic work, however, this may not be 
possible, and the systematist, just as in dealing with archeological or fossil 
remains, may here have to make the most of samples and fragments in lieu 
of specimens. Cultural help and anatomical evidence sometimes lead to 
approximate conclusions; often, however, as with neutral species, definite 
determination must await the communication by the field botanist of adequate 
material. Even then a difficulty, comparable with that frequently met with 
in archeological and paleobotanical study, may be encountered. As archeo- 
logical or fossil material may, owing to the conditions to which it has been 
uva2 
