ON THE LICHENS OF DILLENIUS 's C HISTOEIA MUSCOBUM.' 553 



Muscorum 



by his Herbarium. By the Rev. James M. Ce^tbie, 



F.L.S. &c. 



[Eead December 18, 1879.] 





Through the courtesy of Professor Lawson, I have recently had 

 the opportunity of examining the lichens in the herbarium of 

 Dillenius, which is preserved in the Botanic Gardens at Oxford. 

 As the synonymy and nomenclature of the eai'lier writers on 

 Cryptogamic botany were in a great measure taken from his de- 

 scriptions and figures, it is evidently of the greatest importance 

 to know exactly, from the specimens extant in his herbarium, 

 what species and varieties these descriptions and figures really 

 denote. In so far as the lichens * are concerned, no systematic 

 examination of his herbarium has hitherto been made by any 

 lichenist, although individual specimens have been examined by 

 some of our earlier and premicroscopical writers, e. g. Lightfoot 

 (vid. t Flora Scotica,' ii. p. 801 &c.) and Turner (vid. Linn. Soc. 

 Trans, vii. pp. 109-112). In all other cases (e. g. Linnams, 

 Acharius, Smith in E. B., the indices in the Edinburgh edition of 

 Dill. ' Hist. Muse.' and in Fries, L. E. pp. 464-468, as also in 

 (Krempelhuber's ' Gresch. u. Lit. Lich.' ii. pp. 515-518), the iden- 

 tification of the Dillenian lichens has been simply guess-work ; 

 and it certainly says much for the accuracy of the descriptions 

 and figures that in a considerable number of instances, such has 

 proved to be quite correct. A3 will be seen, however, from what 

 follows, numerous and serious mistakes have been committed 

 which could be corrected only by the due examination of the spe- 

 cimens themselves. In the determination of several critical spe- 

 cies, more especially of the genus "Cladonia" I am indebted to 

 the valuable assistance of Dr. Nylander, who, in fact, originally 

 suggested to me the importance to lichenological science of a 

 thorough examination of Herb. Dill. The title prefixed to the 



herbarium, all the specimens in which are duly mounted, is " Spe- 

 cimina Muscorum in Historia Muscorum descriptorum, aggluti- 

 tinata Eebruario 1744." Eor its age it is in a remarkably good 

 state of preservation ; and the specimens, for the most part, are 

 sufficiently large and characteristic. It is arranged by Dillenius 



* The Musci and Hepatica have also recently been examined by Dr. Lind 

 berg ; and the results obtained will no doubt be published. 



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