— 92 — 
mentioned by Tuckerman in the paper, Am. Naturalist Apr. 1868, entitled 
“Can Lichens be identified by Chemical Tests?” He says “ P. caperata 
is reckoned,' ' 'among the species the medullary layer of which gives no indi- 
cation of a red tinge with the reagent. I find yet the contrary the case in 
North American specimens, as well from Arctic American as Texas, etc., 
almost all these states being marked by elevated powdery margins,' ' ' as if 
a var. ulophylla^ see Ach.) filled in this species an analogous place to the var. 
olivetorum ( P . olivaria ) in P . per lata." Tuckerman adds that some speci- 
mens of P. caperata have a normal reaction however. The form as examined 
is distinct and deserves specific rank. 
P. tiliacea Ach. Methodus p. 215. 
Reaction Kt, me. C-J- red. 
P. tiliacea var. vicinior (Hue) Merrill P . vicinior Hue. Li. -Ex. Eu. I. p. 156. 
K+, C=, K(C)I * 
Distinguished from the species and var. subquercifolia by difference is 
reaction, and so far as American examples furnish evidence there is nothing 
else to satisfactorily differentiate with. The writer possesses three examples 
of P tiliacea , identical in lobation, and thecial characters, in fact exactly 
similar to the eye and with microscope, but of which one affords the reaction 
of P. tiliacea, another that of P. vicinior , and the last that of P. subquerci- 
folia K+> at length red. Both Tuckerman and Wille3^ have touched on the 
perplexities attending the use of reagents with P. tiliacea , but the present 
disposition satisfactorily meets all requirements of classification for the P. 
tiliacea forms from Northern America. P. tiliacea v. sublaevigata 
Nyl. of Tackerman’s Synopsis is made synonymous with P. subquercifolia 
by Hue. 
On trunks, 
3634, Stittsville, Ont. ; 3651, Montmorency Falls, Que. ; 597, Brighton, 
Ont. ; 991, Cape Breton; 3509, Algonquin Pk , Ont.; 593' and 592, Ottawa, 
Ont. ; 595, St. Anne’s des Monts River, Que. ; 594, Quebec, J. Macoun. 
596, Canaan Forks, N. B. J. Moser. 
No. 102 D. N. A. Li. belongs here. 
* Group Irregulares Wain. 
P. saxatilis (L.) Ach. Methodus, p. 204. 
Reaction K+> crimson. 
On rocks, trees, old planks, logs, fences and on the earth. 
3647 and 3648, Cap a L’Aigle, Que.; 609,' Truro, N. S. ; 611, Nipigon 
River, Ont. ; 3512, Algonquin Pk., Ont.: 621, Burrard Inlet, B. C. ; 614, Lake 
Nipissing; 622, Red River, Man.; 620, Victoria, V. I.; 629, Comox, V. I.; 
625, Stittsville, Ont. ; 634, Jupiter River, Anticosti; 616, Lower Arrow Lake, 
B. C. ; 643, Jumping Pound Creek, Ry. Mts. ; 640, Victoria, B. C. ; 636, 
Nipigon Lake, Ont.; 638, Cape Breton; 3493, Algonquin Pk., Ont.; 641, 
Brighton, Ont.; J. Macoun. 647, Clearwater Lake, Labrador, A. P. Low; 
625, 627, St. George’s Is., Bering Sea; 630, 618, 592, St. Paul’s Is., Bering 
Sea, J. M. Macoun. 623, Vancouver Is. Dawson. 
