- 67 — 
est. Parmelia per lata Volxis said to differ from its var. olPdetorum Ach. 
by failing to show any red tinge with chloride of lime, the difference already 
recognized being regarded as sufficiently corroborated by the new one. But 
all specimens of P. d live tor um are not so distinguishable. It is much the 
same with P. Icevigata and its var. yevoluta Nyl. (Syn. p. 385), the last 
being now taken and on better evidence to be distinct in species from the 
first. We have here a better marked difference in botanical character, one 
which commended itself as sufficient to Floerke, and at one time to Borrer ; 
and there seems to be no doubt that the original P . revoluta Flk. is discrep- 
ant from common states of P . Icevigata in the chemical respect also.” 
The learned author goes on to say that all his European specimens of P. 
tiliacea afford a distinct reaction, with which only two or three of the rela- 
tively abundant American forms are concurrent. He also finds that Arctic, 
Tropical and Texan forms of P. caparata give a plus reaction when they 
should be minus; that P. physodes Japonica Tuckerm. is plus when the 
physodes group is conceded to be minus ; and that while P. Borreri is recorded 
as plus, no reaction is observable with the specimens in his herbarium. The 
concluding lines of the paper are interesting, for Tuckerman affirms that, 
“these results given with due respect to the experienced authors whose ob- 
servations have been considered, sufficiently indicate that the writer inclines 
to emphasize the doubts with which Dr. Fries has received the supposed new 
criteria of distinction. It remains none the less likelyfrom whatevidence we 
have that the reagents named, capable as they are of instructive application 
to imperfect fragments, may sometimes afford clews to affinity where there 
is little to direct : and thus deserve a place besides the better known solu- 
tion of Iodine on our working tables.” 
In the Genera Lichenum, 1872, Tuckerman in discussing the tendency of 
the Europeans toward species splitting, reiterates his disapproval of chemical 
tests. Referring to what he terms a “ laxity of conception ” regarding speci- 
fic delimitation, he says, “ This is seen at least in the very generally as- 
sumed value of recent experiments on the behavior of lichen-tissues with 
certain chemical tests : species having come at last to have no other meaning 
than a chemical one ; namely, that they exhibit (so far, it is important to say, 
as the examination has gone) a different reaction from forms with which, in 
every other respect, they are admitted to agree.” 
In his Synopsis, Pt. 1, 1882, Tuckerman makes no general allusion to 
chemical tests, such remarks as are noted being limited to instances of per- 
version from the recorded results of the Europeans. It is easy to see that 
chemical tests are viewed with hostility, although his attitude is evidently a 
passive one. In an extract from the Botanical Gazette, April, 1896, Mr. 
Henry Willey, of New Bedford, Mass., briefly takes up the matter of 
chemical tests in relation to the genus Parmelia. The paper, which is en- 
titled. “ Notes on Some North American Species of Parmelia,” catalogues the 
reactions for a number of species, the reagents employed being potassium- 
hydrate and calcium hypochlorite. Willey remarks, “Of the chemical rela- 
tions I am unable to attach absolute specific value to them. There are 
