GENERAL RESULTS 66 1 



as we believe, to the Cycadophyta, belongs ultimately 

 to the phylum which takes its name from the Ferns. 

 We may add that the Gymnosperms, as a whole, 

 may be referred to the same stock, for evidence has 

 recently been adduced that the small group of the 

 Gnetales (the only outstanding Gymnospermous family) 

 may have been derived, by reduction of the floral 

 organs, from forms allied to the Bennettitales. 1 



It thus appears, if the views here taken are justi- 

 fied, that the whole of the Spermophyta, whether 

 Angiospermous or Gymnospermous, were ultimately 

 derived, through primitive Seed-plants of the nature of 

 Pterido'sperms, from the same stock with the Ferns. 

 With this far-reaching conclusion we may conclude 

 our consideration of the phylogenetic results of our 

 studies. 



In bringing these "Studies" to a close, it is well 

 to* recall the necessary limitations of all attempts to 

 unravel the past history of organisms. Our ideas of 

 the course of descent must of necessity be diagram- 

 matic ; the process, as it actually went on, during ages 

 of inconceivable duration, was doubtless infinitely too 

 complex for the mind to grasp, even were the whole 

 evidence lying open before us. We see an illustration, 

 on a Small scale, of the complexity of the problem, in the 

 case of domesticated forms, evolved under the influence 

 of man. Though we know that our cultivated plants, for 

 instance, have been developed from wild species within 

 the human period, and often within, quite recent years, 



1 Arber and Parkin, " Relationship of ihe Angiosperms to the 

 Gnetales," Annals of Botany, vol. xxii. 1908. 



43 a 



