January 19, 1906.] 



SCIENCE. 



91 



proof should always rest upon the writer 

 suggesting the change. It is rather sur- 

 prising to notice how lightly this matter is 

 taken by some, who attempt sweeping 

 changes. It is by no means rare to see a 

 few habitally similar species of a large 

 genus split off and set up as a new genus 

 with scarcely any attempt to give accurate 

 definition to the new group or tell just 

 what traits are of diagnostic value in sepa- 

 rating it. The authors of such work in- 

 dolently and carelessly shift the burden of 

 proof upon others. Their statements re- 

 garding genera are scarcely more than hy- 

 potheses, but unhappily they are expressed 

 not as theories or mere conjectures, but as 

 facts. This, however, is not the worst type 

 of publication on this subject, for it is even 

 more misleading to assign generic charac- 

 ters as in the case of the segregates of 

 Oxalis, for instance, which do not hold 

 good. Do not understand me to say that 

 authors have been intentionally misleading, 

 for I do not believe that to be the case. 

 I merely mean to say that some writers 

 who have made rather free changes in 

 generic classification have taken so lightly 

 their responsibilities in doing so and have 

 felt so little the obligation to present any 

 complete or scholarly proof of their dog- 

 matically stated conclusions, that they have 

 been tempted into rash and hurried asser- 

 tions, which are in many cases decidedly 

 misleading. 



It may perhaps be thought by some that 

 this is unduly hard on writers who have 

 intentionally adopted a lower grade of 

 generic classification than the somewhat 

 ideal one described a few moments ago, 

 who believe in the practicality of treat- 

 ing as genera minor groups of allied spe- 

 cies, although it is by no means maintained 

 that these are sharply defined or non-inter- 

 grading. To this it may be said' that these 

 minor groups, being of a different classifi- 

 catory rank from the larger long-established 



genera, such as Gyperus, CEnothera, As- 

 tragalus, Banimculus and the like, should 

 not in any natural or well-devised system 

 be treated as coordinate with them and bear 

 the name genus, this name having been ap- 

 plied to groups of a superior rank. This 

 seems to me a very important matter. For 

 if it were considered proper to apply the 

 term genus to smaller and smaller groups 

 with more and more vague definition, there 

 is surely no end in sight and no real prog- 

 ress toward a definite and reliable system. 

 To draw an illustration from another sci- 

 ence, it may be noted that each generation 

 sees an added perfection and accuracy in 

 apparatus for physical measurements of 

 space, time and gravity, but the physicist 

 does not feel it necessary on this account 

 to shorten the meter scale, make his clock 

 run faster, or file down the weights of his 

 balance. His old constants remain as 

 treasured acquisitions and it is by careful 

 reference to them that his progress is made. 

 What we need in botanical classification 

 is a series of such constants, a number of 

 graded categories which can be generally 

 endorsed and properly respected. Stand- 

 ards as definite as those of the physicist 

 are, of course, quite unattainable in dealing 

 with the variable and often intergrading 

 groups of organic creation. But where 

 absolute accuracy and uniformity are im- 

 possible, we should the more diligently seek 

 to preserve such standards as exist. As 

 has been pointed out there are but few 

 families of flowering plants which have not 

 been comprehensively treated by monog- 

 raphers who so far as their particular 

 group was concerned have been in a posi- 

 tion to see pretty clearly where it was best 

 to draw generic lines. While it must be 

 admitted that there are many minor differ- 

 ences in the generic concepts exhibited in 

 the scholarly and monumental worksnifeo 

 which I here refer, yet they establish a good 

 usage, which on the whole has a consider- 



