Or THE ' CHALLENGES ' EXPEDITION. 155 



possible, to keep the ordinary solution of iodine at a uniform 

 strength. I have noticed also that lichens recently gathered in a 

 living state show a greater tendency to the development of this 

 secondary reaction, while occasionally, although rarely, the con- 

 verse holds. Besides all this, the vinoso-fulvescent after reaction 

 is perhaps the most common of all such, and betrays differences of 

 tint which no combination of terms will serve to indicate. The 

 estimation of tints nearly related is also difficult, different obser- 

 vers giving different estimates, and these, too, differing at different 

 times. As I am engaged in experimenting in the same direction, 

 I shall defer to another opportunity what I have to say further 

 under this head. 



Mr. Crombie is perhaps right in referring L. cyanocJiroa, Strn., 

 to Z. endoleuca, NyL ; but the "stratum infra hypothecium " is 

 purpurascent, and in the more recent state, when I examined the 

 specimens, the epithecium was also purpurascent, or rather violas- 

 cent, and not blackish. 



Ramalina aulota, Strn., is said to be = P. minuscula, NyL ; but 

 as I have not seen a description of the latter, there is still a 

 doubt. 



Why Dr. Ny lander should object to the term noseriza when he 

 himself uses rhypariza, clilorotiza, &c. in exactly similar circum- 

 stances and from exactly similar Greek words, is beyond my com- 

 prehension. The apothecia have certainly a sickly colour ; and 

 this is all that is implied in the term. I need scarcely say I 

 bold to noseriza. 



Parmelia adepta, Cromb., = P. euplecta, Strn. MS. p. 1.— Mr. 

 Crombie must have seen the name P. euplecta on the paper 

 enclosing the fragment he speaks of, the smaller half of which I 

 retain; and yet he ignores my name entirely, as indeed, with 

 two exceptions, he does the others throughout the MS. 



The blackening of the thallus by K (also stated by me) is most 

 likely owing to something abnormal, as I find that a second ap- 

 plication on another part gives partly negative effects, while 

 the medulla beneath the unaffected portion gives the reactions 

 as stated in MS., viz. yellow in the upper white stratum and 

 red in the lower very thin yellow stratum. 



Verrucaria prostata, Mut., is the proper determination of the 

 fragment in my possession, and not V. cinchona, Ach. 



Melanotheca rhaphidiza, Strn., is a good species and not mM. 

 aciculifera, Nyl. (see MS.). Mr. Crombie might have taken into 



