172 OBSERVATIONS ON TEZIZA CALYCINA. 



We must state that we fail to recognize this difference in the 

 specimens examined. 



Third. — Reaction with tincture of iodine. 

 P. calycina — not becoming blue. 

 P. laricis — becoming blue. 



Whether this be so or not in fresh specimens, and under peculiar 

 circumstances, we do not care to enquire, but, we contend that the 

 iodine test is not trustworthy. We have found by experience that 

 the same specimen which becomes tinted blue by iodine when in a 

 fresh state, if allowed to dry tor some time, and is again moistened, 

 affords no appreciable change ; that all cnps manifestly belonging 

 to the same species, such as P. coccinea, of which there can be no 

 doubt, do not behave themselves in the same manner under treat- 

 ment by iodine. And that change of colour produced by iodine is 

 not infallible evidence of difference in species, but merely of different 

 conditions under which certain individuals may have been developed. 

 That, in fact, the conditions which induce change of colour on the 

 application of solution of iodine to the asci, are the result of what 

 may be termed accidental circumstances, and are not absolutely 

 characteristic of specific forms. 



Our friend, Mr. Phillips, who was at one time an advocate for 

 iodine tests, has, we believe, lost faith in them entirely, as affording 

 reliable evidence of identity or difference of species. We know of 

 no one in this country who is in the habit of examining a larger 

 number of specimens of Peziza than ourselves and Mr. Phillips, 

 amounting to some hundreds of specimens in the year. We have 

 been constantly in the habit of availing ourselves of his services 

 to check and verify our own observations on the minute differences 

 of closely allied species, in jjreparation of the figures for " Myco- 

 giaphia," and yet he never appeals to the iodine test as any con- 

 clusive argument in favour of any of his views. 



Under all these circumstances, and for these reasons, we have 

 thought it desirable at once to state our objections to Dr. Rehm's 

 pro] )0 sal, and at the same time, incidentally, to indicate what we 

 do not regard as safe bases for specific distinctions.* 



Not having seen the species described as P. EUisiana, we are 

 unable to express an opinion, and it would be unfair to do so under 

 these circumstances. The colour of the hairs of the cup, and 

 their scabrous character, in addition to the features of the fructifi- 

 cation, indicate specific differences, which do not come under the 

 restrictions made with regard to the two other forms. 



* Undoubtedly, if a case can be made ont for the recognition of Dr. 

 Eehm's species, and this be identical with Peziza Willkomii of Thumen, 

 which Dr. Rehm admits, then Thronen's name has priority, and no new name 

 can be received. There is no direct evidence that Peziza WiUkomii, Hart., 

 is different from Thumen's plant, with which the published figures of Peziza 

 calycina, Willkom, will accord equally well as any other form of P. calycina. 



