THE COLORS OF ANIMALS AND PLANTS. 



45 



another. Mr. Darwin himself first worked out 

 the details in orchids, primulas, and some other 

 groups ; and hardly less curious phenomena have 

 since been found to occur, even among some of 

 the most regularly-formed flowers. The arrange- 

 ment, length, and position, of all the parts of the 

 flower are now found to have a purpose, and not 

 the least remarkable portion of the phenomenon 

 is the great variety of ways in which the same 

 result is obtained. After the discoveries with re- 

 gard to orchids, it was to be expected that the 

 irregular, tubular, and spurred flowers, should 

 present various curious adaptations for fertiliza- 

 tion by insect-agency. But even among the open, 

 cup-shaped, and quite regular flowers, in which it 

 seemed inevitable that the pollen must fall on the 

 stigma, and produce constant self-fertilization, it 

 has been found that this is often prevented by a 

 physiological variation — the anthers constantly 

 emitting their pollen either a little earlier or a 

 /ittle later than the stigmas of the same flower, 

 or of other flowers on the same plant, were in the 

 best state to receive it ; and as individual plants 

 in different stations, soils, and aspects, differ 

 somewhat in the time of flowering, the pollen of 

 one plant would often be conveyed by insects to 

 the stigmas of some other plant in a condition to 

 be fertilized by it. This mode of securing cross- 

 fertilization seems so simple and easy, that we 

 can hardly help wondering why it did not always 

 come into action, and so obviate the necessity for 

 those elaborate, varied, and highly-complex con- 

 trivances found in perhaps the majority of col- 

 ored flowers. The answer to this of course is, 

 that variation sometimes occurred most freely in 

 one part of a plant's organization, and sometimes 

 in another, and that the benefit of cross-fertiliza- 

 tion was so great that any variation that favored 

 it was preserved, and then formed the starting- 

 point of a whole series of further variations, re- 

 sulting in those marvelous adaptations for insect 

 fertilization, which have given much of their va- 

 riety, elegance, and beauty, to the floral world. 

 For details of these adaptations we must refer 

 the reader to the works of Darwin, Lubbock, 

 Herman Midler, and others. We have here only 

 to deal with the part played by color, and by 

 those floral structures in which color is most dis- 

 played. 



The sweet odors of flowers, like their colors, 

 seem often to have been developed as an attrac- 

 tion or guide to insect fertilizers, and the two 

 phenomena are often complementary to each 

 other. Thus, many inconspicuous flowers — like 

 the mignonette and the sweet-violet — can be dis- 



tinguished by their odors before they attract 

 the eye, and this may often prevent their be- 

 ing passed unnoticed ; while very showy flowers, 

 and especially those with variegated or spotted 

 petals, are seldom sweet. White, or very pale 

 flowers, on the other hand, are often exces- 

 sively sweet, as exemplified by the jasmine and 

 clematis ; and many of these are only scented 

 at night, as is strikingly the case with the 

 night smelling stock, our butterfly orchis (Ha- 

 benaria chlorantha), the greenish-yellow Daphne 

 pontica, and many others. These white flowers 

 are mostly fertilized by night-flying moths, and 

 those which reserve their odors for the evening 

 probably escape the visits of diurnal insects which 

 would consume their nectar without effecting 

 fertilization. The absence of odor in showy 

 flowers and its preponderance among those that 

 are white may be shown to be a fact by an ex- 

 amination of the lists in Mr. Mongredien's work 

 on hardy trees and shrubs. 1 He gives a list of 

 about one hundred and sixty species with showy 

 flowers, and another list of sixty species with 

 fragrant flowers ; but only twenty of these latter 

 are included among the showy species, and these 

 are almost all white-flowered. Of the sixty spe- 

 cies with fragrant flowers, more than forty are 

 white, and a number of others have greenish, 

 yellowish, or dusky and inconspicuous flowers. 

 The relation of white flowers to nocturnal insects 

 is also well shown by those which, like the even- 

 ing primroses, only open their large white blos- 

 soms after sunset. The red Martagon lily has 

 been observed by Mr. Herman Miiller to be fer- 

 tilized by the humming-bird hawk-moth, which 

 flies in the morning and afternoon when the 

 colors of this flower, exposed to the nearly hori- 

 zontal rays of the sun, glow with brilliancy, and 

 when it also becomes very sweet-scented. 



To the same need of conspicuousness the com- 

 bination of so many individually small flowers 

 into heads and bunches is probably due, pro- 

 ducing such broad masses as those of the elder, 

 the guelder-rose, and most of the Umbelliferas, or 

 such elegant bunches at those of the lilac, labur- 

 num, horse-chestnut, and wistaria. In other cases 

 minute flowers are gathered into dense heads, as 

 with Globularia, Jasione, clover, and all the Com- 

 posite; and among the latter the outer flowers 

 are often developed into a ray, as in the sunflow- 

 ers, the daisies, and the asters, forming a starlike 

 compound flower, which is itself often produced 

 in immense profusion. 



1 " Trees and Shrubs for English Plantations," by 

 Augustus Mongredien. Murray, 1S70. 



