152 CORRESPONDENCE. 
Dr. Nylander’s Criticisms on Mudd's ‘ Herbarium Lichenum 
Britannicorum, 
Great Ayton, Stokesley, Yorkshire, April 14, 1863. 
Whilst I feel most grateful to Dr. — for pointing out, in the Ratisbon 
Flora, the discrepancies and errors in the * Herbarium Lichenum Britanni- 
corum; fasc. i.—iii, E cannot but deplore the cemere manner in which 
these reputed errors have been exhibited. | On the face of his assertions there 
an exhibition of critical accuracy on his. "The principal object ler above 
work, and of the ‘Manual of British Lichens, was to incite a more critical 
study and examination of the species of this country, concluding hd, if such 
object could be accomplished, the interchanging of opinions respecting doubt- 
species, their classification, ete., would naturally follow, and materials would 
be collected from which ultimately a work might be produced critically cor- 
rect. I never anticipated that this exchanging of opinions would be ĉon- 
in any other than in the most amicable manner. To analyse or in- 
investigator give to the world the result of his investigations ; but let this be 
behind. © Criticism is a correct path to truth, as well as an excellent mode of 
elucidating obseure or ambiguous reasoning; but criticism for the mere sake of 
criticism is nothing more than the employment of talent for the self-aggrandise- 
Allow me, in the first instance, to mnaee Dr. Nylander’s observations on 
fasciculi i.-iii. of my * British Lichens : 
“1, Collema pulposum is C. yore var. tenaz, Ach., approaching /imosum, 
Ac -- : 
4. Leptogium eR aod: is L> spongiosum, Nyl. 
10. Cladonia gracilis, ar. hybrida, is C. gracilis, f. chordalis, Fik. 11 is 
the same, ‘ sterilescens DOM fera." 
a Cladonia d. ns is C. erispata, Ach., spermogonifera. 
Cladonia Surcata, var. racemosa, is C. Surokia; var. prona Ach. 
e Cladonia furcata, var. pungens, is C. uncialis, var. bolacina, Ach. ; 18 is 
same in various forms. 
.. 93. Cladonia coccifera, var. bellidiflora, is C. macilenta, var. Pegs Ach. 
24. Cladonia Flerkeana is like C. macilenta, var. corcata, 
= Cladonia digitata consists of various d of C. reden Hoffm. 
oninia barbata, var. plicata, is U. ceratina, Ach. 
lauca, var. fallaw, is piri ulophyll m, Ach. 
i. Peltigera aphthosa is Peltidea aphthosa, var. Fem Nyl. 
61. Peltigera polydactyla is P. polydactyla, var. hymenina, Ach. 
66. Is Parmelia sulcata, Tayl. 
71. Parmelia aleurites is Parmeliopsis placorodia, Ach., Nyl. 
72. Parmelia olivacea is P. exasperata, Ach. i 
81. Borrera obscura, var. chloantha, is Physcia stellaris, f. rosulata, Ach. 
ia 
