472 



SCmNCE^ 



[N. S. Vol. XIV. No. 352. 



unswerving desire to find out and record 

 the exact truth. I do not mean to im- 

 ply that systematists to-day have not this 

 desire. Unfortunately, however, many of 

 them, perhaps all, seem never to escape a 

 certain hypnotism caused by particular in- 

 terests. Trifling matters assume undue im- 

 portance. Little difierences seem so great 

 as to obscure the preponderating similari- 

 ties, or, on the other hand, superficial like- 

 ness blinds the observer to every difl^ering 

 detail. An opinion is quickly formed and 

 perhaps hastily published. It then becomes 

 a matter of personal pride to maintain it, 

 and if any one expresses a doubt concerning 

 its accuracy he is promptly called out to a 

 controversial duel. 



Kow these things have their bright side 

 and are in their milder form diverting, for 

 somehow after the scrimmage which fol- 

 lows, truth, for the time hidden by the dust 

 of combat, usually shines forth in victory, 

 or more often becomes evident as the re- 

 sult of compromise. Indeed controversy is 

 perhaps the only means which will success- 

 fully dispel the narrowing and perverting 

 influence proceeding from the intensive ex- 

 amination of small details, and so often 

 blinding the systematist to the real per- 

 spective of his own observations. 



If we now turn from the matter of varia- 

 tion to that of distribution, it is equally 

 evident that only a beginning has been 

 made, that inferences are drawn from very 

 insufficient material and that a vast accu- 

 mulation of further data is requisite to ac- 

 curate results. Let any one who doubts 

 try to bound the range of some common 

 species, to draw upon a map the sinuous line 

 connecting the outermost recorded stations. 

 The gaps are astonishing. Great lacunae 

 quickly appear in our knowledge of plant 

 distribution. 



No one can doubt the value of much 

 fuller records in this department of our 

 subject, nor maintain that our knowledge 



of any plant is satisfactory until the limits 

 of its natural occurrence are accurately de- 

 termined. While plant distribution, studied 

 from the ecological side, has become a popu- 

 lar subject, comprising many useful obser- 

 vations and theories both valuable and 

 fascinating, the actual record of plant- 

 ranges is on the whole regarded as rather 

 dry business and is a field of investigation 

 in which laborers are few. Mention should 

 be made, however, of Professor A. S. Hitch- 

 cock's admirable work in this direction 

 upon the flora of Kansas. What notable 

 advance might be made if each State of our 

 Union could have an equally well-trained 

 systematist similarly interested in this 

 matter of plant distribution ! 



Could we but know the actual curving 

 boundaries of a few hundreds of our best- 

 defined species, what a wealth of new gen- 

 eralizations could be drawn from them, and 

 how much new information they would 

 yield concerning the factors which govern 

 distribution in general ! For, irregular as 

 these lines would be, I can but think that 

 they would in many cases stand in definite 

 relation to lines of other kinds, to isother- 

 mals, to altitudinal contours, to degrees of 

 humidity, to the boundaries of geological 

 formations, the limits of glaciation, the 

 ranges of animals, especially pollen- bearing 

 insects, to the paths of bird-migration, and 

 finally, to the course of human traffic. 

 What a field for further investigation is 

 thus suggested by our still very imperfect 

 knowledge of plant boundaries ! It is a 

 field, too, which the careful amateur can 

 cultivate almost as easily and as well as the 

 professional botanist. Every one lives near 

 the assumed limits of some plants and 

 might, by directing his attention to the 

 subject, do much to change these as yet 

 vague and hypothetical boundaries into ac- 

 curately determined and carefully recorded 

 lines. 



Not only would these lines be likely to 



