vm INTRODUCTION. 



creations, requires the recommendation of proof. All our 

 Floras tell a different tale. The links which once connected 

 Equisetum to Chara or to Isoetes have since perished, and 

 no others have heen supplied ; so that those genera stand 

 alone and insulated, while all around them has disappeared : 

 just as solitary specks of uninhabitable land, peeping up in 

 the boundless ocean, are said to testify of a continent sub- 

 merged. Whoever reads these circumstances aright, will fully 

 appreciate the difficulty under which those are labouring who 

 endeavour to build a system of such scanty materials. Deeply 

 impressed with this difficulty, I have thought it better to 

 preserve intact the arrangement which I originally proposed, 

 than to attempt a new one ; at the same time giving an out- 

 line of a plan which I believe more in accordance with Nature. 



It may here be observed, that in the various systems 

 proposed or indicated by general botanists, as Ray, Linneus, 

 Antoine de Jussieu, Agardh, Perleb, Dumortier, Bartling, 

 Hess, Schultz, Fries, Endlicher, Brongniart, Meisner, Adrian 

 de Jussieu, and Lindley, there is a most evident tendency to 

 depreciate, or rather to under-estimate, the flowerless plants. 

 Whether they were called simply " flowerless," as by Ray ; 

 "Cryptogams," as by Linneus; " Acotyledons, " as by the 

 elder Jussieu and DecandoUe ; little has been done beyond 

 the mere change of name. All these authors appear either to 

 ignore or to disregard the extreme fallacy of divisions founded 

 on a mere positive and negative. Nothing is more simple than 

 the division of all plants into those wliich have flowers, and 

 those which have not : but something more is required, for 

 positive and negative characters might be made the basis of 

 the most unnatural divisions. 



Cuvier, in his 'Animal Kingdom,' a work unapproached, 

 perhaps unapproachable, in its masterly and philosophical 



