PLAN OF THIS BOOK 



streaks or lines of color found on the stems of some insect- 

 devouring plants which lead straight to the smooth, fatal 

 rim of the cup. 



Evolution of Color in Flowers 



Colors of flowers, we may believe, were evolved somewhat 

 in this way: A flower, hitherto white or green, showed by 

 chance a bit of red or yellow, blue or pink, perhaps only a 

 streak or dot. Insects were attracted to that flower, and 

 it was pollinated, while others lacking the color may have 

 been neglected. The tendency of both plants and animals 

 to reproduce marked traits of their parents is well known. 

 The young plant springing from the marked flower would 

 probably reproduce the color rather more strongly, and its 

 offspring more strongly still. In time, perhaps after many 

 generations, a perfectly colored flower would be the result. 



We therefore judge that those flowers which have evolved 

 color are high in rank. By the rank of a plant is meant the 

 place it holds in the ascending series from simplest and low- 

 est to the most complex, the most highly organized, and 

 the most successful in securing its own dissemination and 

 propagation. 



Flowerless plants, the algas, mosses, and ferns, appeared 

 first on the earth. These were succeeded by "wind lovers," 

 flowers like those of pines and hemlocks, which are polli- 

 nated by the wind. The wind blows impartially, caring 

 not at all for the fair spread of the lily bell or the soft scent 

 of the violet. No color has, therefore, appeared in flowers 

 which are pollinated by the wind. 



"Insect lovers" alone are colored and fragrant. Some- 

 times dull flowers are surrounded by red or yellow bracts, 

 as in the painted cup {Castillcja coccinca). Night-blooming 

 flowers, adapted to night-flying moths, sometimes keep their 

 petals shut in the daytime; for the right insect isf wanted 

 by a flower. Insects too large or too slim, or in any way 

 unsuited to the shape of the flower, do not make good pollen- 

 carriers, and the methods for keeping them away make an 

 interesting chapter. Flowers adapted to flies often evolve 

 fetid odors such as flies like. Bees generally avoid the 

 ill-odored flowers, and turn to the honeysuckle or clover 

 blossom. 



