attention, and plays the principal part in the earlier arrange- 

 ment of our plants : as in the three genera (Usnea, Coralloides, 

 Lichenoides) in which they are brought together in the disposi- 

 tion of Dillenius ; and the single genus (Lichen) under which 

 they are arranged, in sections limited by thalline differences, by 

 Linnaeus. And the thallus has continued to commend itself to 

 systematists even after the explication of the whole lichen-or- 

 ganism : as to Fee, in 1824 ; and as exhibited in the well-known 

 Sy sterna of Koerber. (*) 



Study in any sufficient sense, begins however, in the order 

 of time, with the next succeeding stage of inquiry, wherein the 

 thallus is accepted only as the ground of a further develop- 

 ment as existing for the behoof of other essential organs, and 

 we have before us all that constitutes the organism the whole 

 plant. The systematic disposition of Nylander reckons thus all 

 organs, or, more particularly, thallus, spermogones, and apo- 

 thecia, as of equal value in the system ; and his arrangement 

 proceeds eclectically, as now one and now another conspicuous 

 character is assumed as determinative (Syn. Lich. 1, chap. x). 

 But great as is the advantage which this disposition enjoys as 

 the means of communication of the author who has described 

 and is describing more lichens than any other, it is easily seen 

 that it differs from other systematic works not at all, as the au- 

 thor would imply, in the exclusion of selection (that is, of the 

 'artificial and arbitrary'), but only in the use made of it. Not 

 to dwell here on the treatment of near and remote affinity, or of 

 affinity and analogy, in this arrangement evidenced by the 



(*) We cannot well refer, in this connection, to Dr. Th. Fries's elabo- 

 rate Scandinavian Lichen-Flora (1871-1874), the principle of construc- 

 tion of which is the gonimons system, as but little as respects the evolu- 

 tion of the method has yet been published. But however greatly the 

 significance of the gonimous cells may be advanced by more recent re- 

 search, their anatomy and morphology are still but imperfectly known ; 

 and it is difficult to conceive that much can be gained from what must 

 necessarily be arbitrary views of only a part of the phenomena. 



