218 THE FLOWER. 



nearest source, testifies to these particulars. All amentaceous 

 trees (Willows excepted), Hemp, Hops, &c., are wind-fertilized ; 

 and, among perfect flowers, those of most Grasses, Sedges, and 

 Plantago. In the latter families especially, the anthers are pro- 

 truded or hung out in the air only when just ready to discharge 

 their pollen, and are at that moment suspended on suddenly 

 lengthened capillary drooping filaments, fluttering in the gentlest 

 breeze ; and the stigmas are either dissected into plumes, as in 

 most Grasses, or beset with copious hairs on which pollen is 

 caught. One physiological adaptation, very common in the fol- 

 lowing class, is not unknown among hermaphrodite wind-fertiliz- 

 able flowers, where it is important for securing intercrossing, viz. 

 Dichogamy. It is best seen in the common species of Plantago 

 or Plantain, and is described below. (408.) 



404. Insect-fertilizable or entomophilous flowers are correlated 

 with showy coloration (including white, which is most show} 7 at 

 dusk), odor, or secretion of nectar, often by all three modes of 

 attraction to insects combined. Some insects, moreover, visit 

 flowers for their pollen, a highly nutritious article, and ordina- 

 rily produced in such abundance that much ma} r be spared. 

 The showiness of corolla or other floral envelopes is an attractive 

 adaptation to fertilization, enabling blossoms to be discerned at 

 a distance ; nor do we know that fragrance or other scent or 

 that nectar subserves any other uses to the flower than that of 

 alluring insects. Adaptations in the pollen of such blossoms 

 for transportation by insects are various. Common!}' the grains 

 are slightly moist or glutinous, or roughish, or studded with 

 projections, or strung with threads (as in CEnothera), so as not 

 to be readily dispersed in the air, but to have some slight 

 coherence as well as capability of adhering to the head, limbs, 

 or bodies of insects, especially to their rough surfaces ; and 

 in two families (Orchidaceae, Asclepiadaceae) the pollen is com- 

 bined in masses and with special adaptations for being trans- 

 ported en masse. (421.) With this the stigma is usually 

 correlated, by roughness, moisture, or glutinosity. 1 



405. Adaptations of the flower itself in reference to insect 

 visitation are wonderfully various ; and most of these are found 

 upon investigation to favor, or often to necessitate, intercross- 

 ing. In difficious flowers, this is necessitated by the separation ; 

 in monoecious and polygamous flowers, of various kinds and 



1 Thus nearly every Orchid genus but one has a persistently glutinous 

 stigma ; in the exceptional one, Cypripedium, it is moist and minutely rough- 

 ened, in correlation with the loosely granular or pultaceous pollen which it 

 is to receive. 



