420 Rev. W. A. Leigliton on the Cladonise of Bavaria. 



LII. — Notido3 Lichenologicw. No. XXIX. 

 By the Rev. W. A. Leighton, B.A., F.L.S. 



To the generous kindness of Dr. Rehm, of Sugenheim, Bavaria, 

 I am indebted for a copy of his recently published first fasci- 

 culus of Cladonice of Bavaria. It contains fifty specimens, 

 well preserved, in beautiful condition, and carefully mounted. 

 They are enumerated below, with the names, &c, on the at- 

 tached labels. To these I have appended the results of che- 

 mical tests, which are precisely similar to those uniformly met 

 with in an examination of thousands of specimens in all sorts 

 of conditions and from all parts of the world, embodied in the 

 herbaria of D. Turner, Borrer, and Hooker at Kew, and of 

 which a detailed account is given in Not. Lich. No. XII. A 

 few references are made to published collections by way of 

 identification, and an occasional note as to possible differences. 



In my experience, the best way to apply the chemical tests 

 is with small brushes made of finely spun glass, merely mois- 

 tening the cortical layer. There is no need of friction, for the 

 reaction is instantaneous. 



The student is especially warned against misconception as 

 to chemical tests constituting a sole specific character. All 

 that has been ever asserted respecting them is that they afford 

 an additional and confirmatory specific character. And in 

 those cases where external characters are similar or approxi- 

 mate, and doubt necessarily exists, their value as such will be 

 abundantly apparent. For proof, reference may be made to 

 the results of an examination of the Acharian specimens in 

 Mr. D. Turner's herbarium, and those in the Borrerian herba- 

 rium, at Kew (see Not. Lich. No. XII.). 



In these investigations the student will do well to bear 

 constantly in mind the following admirable caution of Dr. 

 Nylander (see Journ. Linn. Soc. ix. p. 365, note) : — " The 

 analyses of lichens made by chemists often fail through the 

 neglect of an exact determination of the species, and probably 

 not less often by the mixture of specimens confounded together 

 and incorrectly assigned to one single species. For the chemist 

 no less than for the physiologist it is of the greatest importance 

 to know exactly what is the plant we have under observation 

 ■ — that is, to have well determined the plant which we are 

 studying." In other words, he must not place implicit confi- 

 dence on the attached labels as indicating undoubted accuracy, 

 or on his own preconceived notions of the particular diagnosis, 

 but by careful observation and comparison thoroughly satisfy 

 himself that the plant under review is really that which the 



