of the Herbarium of Acharius. 313 



his herbarium at Rostock hundreds of specimens which he was 

 unable to refer to any one of his types. 



Some faulty determinations here also disfigure the Acharian 

 herbarium : thus we find in it an entire series of C. deformis, 

 from Sweden, under the name of C. fimbriata ; and C. macilenta, 

 from Switzerland, under that of C. fimbriata fibula ; the typical 

 C. pyacidata and its variety chlorophcea are intermingled with 

 fimbriata', and some specimens of C. cenotea bear at the same 

 time, though with a mark of doubt, the two names of cenotea 

 and o( fimbriata. 



13. Cladonia gonorega, (Ach.) Syn. p. 258 et hb. ejusd. 



When I examined, in the Acharian herbarium, and still more 

 in that of Florke, the long series of specimens intended to justify 

 the varieties created by these authors, I could not refrain from 

 asking what advantage science could possibly derive from such 

 numerous and subtle distinctions. They rather serve to em- 

 barrass than facilitate lichenology, and are by no means suffi- 

 cient to denote all the forms of a species so variable as C. dege- 

 nerans. Moreover the herbarium at Helsingfors contains, under 

 the name of forma variantes, more than forty specimens of this 

 species which Acharius was unable to compress into his classi- 

 fication. 



In my opinion, the forms aplotea, euphorea, anomcea, pleolepis, 

 iepidota, cladomorpha, polyphaa, scabrosa, virgata, and graciles- 

 cens do not deserve to be distinguished as particular forms ; and 

 this is also the opinion of Acharius himself (Syn. p. 258), "vix 

 sub nominibus singularibus denotari merentur." 



The form trachyna is more remarkable, and especially more 

 easily recognizable ; it may therefore be retained by uniting 

 with it the forms lepidota, pleolepis, and virgata. 



As to the variety nivea, Ach. (Syn. p. 260), it belongs to C. 

 pungens, Flk. ; and Acharius, on revising his herbarium, after 

 his Synopsis was printed, unites it with that species. 



Notwithstanding these diminutions, C degenei'ans will still 

 reckon a certain number of varieties ; for the forms hypophylla, 

 pleolepidea, and basima, recently described by Dr. W. Nylander 

 (Lich. Scand. p. 54), appear to me sufficiently remarkable to be 

 elevated to the rank of varieties. I have this summer found all 

 these forms in great abundance on the borders of the Baltic Sea, 

 both in Sweden and Russia. 



The Acharian herbarium here also contains many erroneous 

 determinations : thus, under the name of gonorega appear a 

 specimen of C. turgida, from Sweden, two of C. pyxidaia, in a 

 proliferous state, from Switzerland, and a tuft of C. furcata 

 crispatella, Flk., from Sweden. Two forms of C. glauca, Flk., 



Ann. ^ Mag. N. Hist. Ser. 3. Vol. xviii. 22 



