FERTILIZATION IN THE VEGETABLE KINGDOM. 227 



As to cross-fertilization, "the most important of all the 

 means by which the pollen is carried from^the anthers to the 

 stigma of the same flower, or from flower to flower, are in- 

 sects, belonging to the orders of Hymenoptera, Lepidoptera, 

 and Diptera ; and in some parts of the world, birds." In a 

 note the author cites all the cases known to him of birds fertil- 

 izing flowers. These are chiefly humming-birds. " In North 

 America they are said to frequent the flowers of ImjDatiens " 

 (for which Gould, " Trochilidse," is referred to as authority, 

 and a reference is given to the " Gardener's Chronicle," which 

 we find relates to something else in South America) ; and this 

 is all concerning the United States. Can it be that there are 

 no references in print to the most familiar fact that our hum- 

 ming-bird is very fond of sucking the blossoms of Trumpet 

 Creeper ( Tecoma radicans) and of Honeysuckles ? Both 

 these are, in size and arrangement of parts, well adapted to 

 be thus cross-fertilized. 



Flowers are rendered conspicuous to birds and still more to 

 insects, by bright colors. And as " almost every fruit which 

 is devoured by birds presents a strong contrast in color with 

 the green foliage, in order that it may be seen and its seeds 

 disseminated," so the proportionally large size and the bright 

 colors of the corolla, or, in some cases, the equally bright hues 

 of the adjoining parts of the flower, or of the inflorescence, 

 are correlated to visiting insects, — have come to pass, as Dar- 

 win would say, in consequence of the visits of insects, through 

 the advantages in vigor and productiveness gained by cross- 

 fertilization. He is ready to adopt even the idea of Conrad 

 Sprengel, which seemed to be so fanciful, that marks and 

 streaks on the corolla serve as guides to the nectary ; for, 

 although insects are well able to discover the nectar without 

 the aid of guiding marks, yet they are of service by facilitating 

 the search and enabling insects to suck a greater number of 

 blossoms within a given time, which is tantamount to greater 

 opportunity for cross-fertilization. 



That odors attract insects is certain, and many flowers are 

 both conspicuous and odoriferous, while others make up in 

 fragrance what they lack in show. " Nageli affixed artificial 



