from Premature Dislodgment or Moisture. 435 



positions with regard to the horizon ; they then most fre- 

 quently open in such a manner that at the moment when the 

 pollen would be exposed to inclement weather the opening of 

 the corolla looks towards the ground, and thus the rain may 

 pour upon them without injury. 



Such are the different peculiarities of organization, the special 

 object of which is to facilitate fecundation by protecting the 

 pollen from accidents which might injure it, without, however, 

 presenting any obstacle to the free access of insects whose 

 business it is to cooperate in the accomplishment of that func- 

 tion. Of course these different means are often combined : for 

 example, if a flower in closing at night leaves an aperture at 

 the apex of the corolla, it will be borne upon a more or less 

 curved peduncle. 



In a general way we may say that the pollen is more com- 

 pletely protected in proportion as it is less abundant and more 

 coherent, and in proportion as the fecundation is more absolutely 

 subjected to the intervention of insects, the time of anthesis 

 short, and the climate less favourable. 



Thus the Orchideas perhaps present the most complete com- 

 bination of all the means of protection, which is in perfect ac- 

 cordance with the nature of their pollen and the small number 

 of their flowers. In the Pomacea? and Amygdalea?, on the 

 other hand, the stamens are very numerous, and the flowers 

 are so abundant that if only half of them developed fruit the 

 tree could never bear its load. Hence the means of protection 

 employed are very rudimentary. 



Even a superficial glance over the flora of a country will 

 generally show an intimate relation between the climatal 

 conditions and the structure of the most wide-spread families. 

 A cold and humid region (where fecundation will always be 

 difficult and where the flowers must sometimes wait for several 

 days for a ray of the sun to favour the issue of insects) cannot 

 fail to exert a marked influence upon the character of its flora. 

 It is thus that in the Alps, where the dews are very heavy and 

 where persistent clouds often cover the summits for whole days, 

 the dominant genera (Gentiana, Primula, Andromeda, Solda- 

 nella, Pedicularis, Campanula, Euphrasia, Veronica, &c.) all 

 possess complete means of sheltering their pollen. No plants 

 with ephemeral flowers occur there ; and in none do the stamens 

 rise much above the corolla. If, on the other hand, we take 

 as a point of comparison the flora of the south of Australia, a 

 region where during the season when plants flower not a drop 

 of water falls, we find that the Mimosa?,, My rtacece, arid Proteaceoe 

 (which are so abundant there) all have rigid flowers with very 





