402 ANEMOPHILOUS PLANTS. CHAP. X. 



I have already made some remarks on the structure of 

 their flowers in contrast with those of entomophilous 

 species. There is good reason to believe that the first 

 plants which appeared on this earth were cryptogamic ; 

 and judging from what now occurs, the male fertilising 

 element must either have possessed the power of spon- 

 taneous movement through the water or over damp 

 surfaces, or have been carried by currents of water to 

 the female organs. That some of the most ancient 

 plants, such as ferns, possessed true sexual organs there 

 can hardly be a doubt ; and this shows, as Hildebrand 

 remarks,* at how early a period the sexes were separated. 

 As soon as plants became phanerogamic and grew on 

 the dry ground, if they were ever to intercross, it would 

 be indispensable that the male fertilising element 

 should be transported by some means through the 

 air ; and the wind is the simplest means of transport. 

 There must also have been a period when winged 

 insects did not exist, and plants would not then have been 

 rendered entomophilous. Even at a somewhat later 

 period the more specialised orders of the Hymenoptera, 

 Lepidoptera, and Diptera, which are now chiefly con- 

 cerned with the transport of pollen, did not exist. 

 Therefore the earliest terrestrial plants known to us, 

 namely, the Coniferae and Cycadeae, no doubt were ane- 

 mophilous, like the existing species of these same 

 groups. A vestige of this early state of things is 

 likewise shown by some other groups of plants which 

 are anemophilous, as these on the whole stand lower 

 in the scale than entomophilous species. 



remark that plants must have came nectariferous and gradually 



been anemophilous before they acquired their present structure 



were entomophilous. H. Miiller through successive beneficial 



further discusses in a very in- changes. 



teresting manner the steps by * ' Die Geschlechter-Vertheil- 



which entomophilous flowers be- ung,' 1867, pp. 84-90. 



