of the Herbarium of Acharius. 307 



rium (and also of those of Delise, in the Museum of Paris, and 

 of Florke, at Rostock, the results of which will form separate 

 papers) is to fix the synonymy of the species and the diverse 

 varieties of these authors, to simplify the nomenclature by 

 the suppression of a great number of useless varieties, and to 

 indicate some new ideas on a certain number of the species, 

 — thus constituting a prodromus for a new monograph of the 

 genus Cladonia. 



1. Cladonia papillaria, Hffm., (Ach.) Syn. p. 248 et hb. ejusd. 



This species, although poorly represented in the Acharian 

 herbarium, is found there in all states of development, except 

 with perfect apothecia. The localities indicated, as for most of 

 the other species, are France, Germany, and Sweden. 



2. Cladonia retipora, (Ach.) Syn. p. 248. 



No specimen. Acharius knew it only from the description 

 and figure of Labillardiere. 



3. Cladonia ccBspititia, (Ach.) Syn. p. 249 et hb. ejusd. 



The specimens are very insignificant. A specimen from Lap- 

 land merits notice by reason of the high latitude of its habitat. 



Most modern lichenographers consider C. caspititia to be a 

 distinct species, whilst others regard it as a variety of C. squa- 

 msoa. Frequent study and observation of this plant in the 

 woods of Heverle, near Louvain, and in the pine-forests of 

 Meirelbeke, near Gand, convince me that it is only a variety of 

 Cladonia pyxidata, pityrea. On some oaks in the wood of He- 

 verle, now unfortunately felled, I have for many years observed 

 all the transitions between C. fimhriata (Ach.) and C. pityrea 

 (Ach.), and between this latter and C. caspititia. I believe, 

 therefore, we must henceforth regard C. caspititia as a variety 

 of C. pyxidata (L.) . 



4. Cladonia strepsilis, (Ach.) Syn. p. 249 et hb. ejusd. 



This Acharian species has always been problematical. Dr. 

 Nylander, who had examined the Acharian herbarium, refers it 

 to C. caspititia (Lich. Scand. p. 57, and Syn. p. 211) ; on the 

 contrary, Florke, who had also examined the Acharian speci- 

 mens, recognizes it only as a sterile and macrophylline form of 

 C. cariosa (Comm. p. 14). In reality, both these learned li- 

 chenologists have foundation for their opinions. The principal 

 specimen of C. strepsilis of Acharius (alone preserved entire, for 

 the others have been mutilated) is positively the C. caspititia ; 

 but the v&riety plumosa (Ach. Syn. p. 250) is a sterile form of 



