72 POPULAR SCIENCE MONTHLY. 



signatures supposed that the color and form of plants indicated 

 their relations, good or evil, to the human race, in reference to 

 which they were especially created. This crude superstition 

 attained greatest favor in the sixteenth century, and is still 

 prevalent in obscure form among the lower classes in certain 

 portions of Europe. The use of colors as a distinguishing 

 mark between species, families, and groups began quite early in 

 the history of attempts at classification, and still forms a minor 

 character in modern systems. A wholly new point of view was 

 that taken by Konrad Sprengel, in his history of the biological 

 significance of color (Das entdeckte Geheimniss der Natur im Bau 

 und Befruchtung der Blumen ; Berlin, 1793). To Sprengel is due 

 the idea that the colors of the secondary reproductive organs are 

 a device for the attraction of insects, thus securing cross-ferti- 

 lization. Investigations in many directions from this idea have 

 revealed the fact that plants in a similar manner attract insects 

 and other animals for many other purposes besides fertilization, 

 and in some instances avoid such visitors, for various reasons 

 connected with their development, in a similar manner. Such an 

 amount of attention has been given to these ecologic color adap- 

 tations that the aggregate mass of the results recorded is nothing 

 short of colossal. That these results are of immense value and 

 importance goes without saying : yet, given such a thesis, it is 

 impossible that the observations of both trained and amateur 

 workers should not contain a large number of misinterpreted 

 facts. The general principle has been drawn upon to furnish 

 solutions to complicated or unusual arrangements of color, in a 

 manner highly improbable and unscientific and in many instances 

 verging upon the impossible and ridiculous. That it can not be 

 assumed a priori that the colors exhibited by the flowers or any 

 other organs of the plant are devices to attract and guide insect 

 visitors is becoming more and more apparent. Timely attention 

 has been called to the perversion of this principle by the writer 

 of a recent article on floral biology (Willis, Science Progress, No. 

 21, 1895). That great care is necessary in the interpretation of 

 areas of color in plants is emphasized by the fact that accumu- 

 lating observations tend to show that a color sense is wholly lack- 

 ing except among the higher insects, and that if the colors of 

 flowers were fashioned to attract insect visitors the directive im- 

 pulse must have been received at a very recent date that is, since 

 the acquisition of the color sense by insects. It is by no means 

 the purpose of this article to discredit the great mass of well-con- 

 firmed facts concerning the uses of the colors as an adaptation 

 to insect visitors, but chiefly to call attention to conclusions 

 afforded by the last fifteen years of research upon the formation 

 and physiological uses of color in plants. The functions sub- 



