COLOR IN FLOWERING PLANTS. Si 



Protective organs or substances are frequently increased in 

 the vicinity of flowers. Long ago Erasmus Darwin wrote : " The 

 flowers or petals of plants are perhaps, in general, more acrid 

 than their leaves; hence they are much seldomer eaten by in- 

 sects." " Many caterpillars will rather die than eat the flowers 

 of the plant whose leaves are their special food." * But insects are 

 not the only foes who steer clear of petals. Kerner gives a long 

 list of plants whose leaves are eaten by herbivora, the flowers 

 untouched. In our own land the blossoms of the waysides and 

 fields — May-weed, buttercups, daisies, dandelions, sorrel, wild 

 carrot, etc. — by their very abundance witness to their immunity 

 from the attacks of grazing animals. \ The survival of many 

 showy flowers in St. Helena, notwithstanding the introduction of 

 goats, which have destroyed the luxuriant forests, may perhaps 

 be due to the beauty which brands them unpalatable. 



The conspicuousness of all of these species is the noteworthy 

 point. They are landmarks, doubtless, to the lower animals as 

 to us. That blossoms are most completely shunned when they 

 are large and showy is almost axiomatic. If bright flowers tasted 

 well, they would be speedily annihilated. The majority of good 

 fodder plants have insignificant flowers.* 



There is still another class of enemies which may be prevented 

 from attacking flowers by the disagreeable chemical properties 

 of their conspicuous petals. These are the birds. Mr. Brock- 

 hurst writes that in the dry summer of 1880 the sparrows, seek- 

 ing pollen, destroyed his crocuses, preferring the yellows to the 

 purples and whites. They also attacked the primroses, devour- 

 ing hundreds of them in one morning. Orioles have been seen to 

 bite through the corollas of the trumpet-creeper and golden cur- 

 rant. Young seeds and soft petal tissues would certainly seem to 

 be dainty bird-fare, and would surely be more often so used were 

 they not chemically protected from such injury. As things are, 

 however, other food seems to be preferred when it can be found. 

 In addition to the need of defense against rain, and of adaptation 

 to the form and size of the chosen visitors, necessity of keeping 

 the pollen, nectar, and ovules from destruction by birds may have 

 helped in the formation of tubular and palated corollas. Flowers 

 need the beauty of Helen to attract lovers, the guile of Penelope 

 to discriminate between the true and the false ; to provide for the 

 one, and against the others. 



IV. Mimicry.— Mr. Bates found in South America and Mr. 

 Wallace in the Malay Archipelago several genera of very abun- 

 dant, brilliant butterflies which birds refused to eat ; and, accom- 



* Kerner. 



f The disagreeable substances are volatile, disappearing when the flowers are dried 

 vol. xlii. — 6 



