Ze WILLIAMS: NOTES ON SOME WESTERN LICHENS 
RHIZOCARPON PETRAEUM (Wulf.) Massal. 
Dawson, very common (Z07). 
PELTIGERA APHTHOSA (L.) Hoffm. 
Lake Lindeman, May, 1898 (34). 
NEPHROMOPSIS CILIARIS (Ach.) Hue. 
Lake Lindeman, April, 1898 (76). 
CETRARIA ISLANDICA CRISPA Ach. 
Lake Lindeman, April, 1898 (15a). 
PARMELIA PHYSODES (L.) Ach. 
Dawson, common, October, 1898. 
One species referred to in Howe’s list, however, I do not find in 
my collection, namely, that under No. 11 in his enumeration, which 
is called Biatora franciscana Tuck. This was part of my collection 
number 56; in what is left everything is evidently Lecanora 
calcarea (L.) Nyl., as determined by Dr. Hasse. 
The remaining notes on Yukon specimens are taken up in 
order, according to Dr. Howe’s numbers, and relate to changes, 
the numbers in parentheses being my collection numbers. 
8. LECIDEA TESSELLATA.Floerke. The specimen (52) was 
sent to Dr. Hasse, and referred to Lecidea, but was ‘‘too fragmen- 
tary for a satisfactory examination,” in his opinion. 
33. LECANORA LENTIGERA (Web.) Ach. On earth of river 
bluff just below Dawson, April, 1899 (64); evidently this, a fine 
and apparently rare species. Another specimen, however (87), 
questionably referred to L. crassa, under the impression that it was 
not distinct from L. lentigera, is certainly quite different from either 
It isevidently L. thamnoplaca Tuck., not previously known north of | 
Montana and but rarely collected. It was first obtained by Bo- 
lander in Nevada and next by Dr. Coulter in Yellowstone Park. 
34. The specimens under this number, called Lecanora thamno- 
placa Tuck., Dawson, April, 1898 (52), are all in my packet 
Lecanora fruticulosa (Dicks.) Ach. 

35. The two collections here referred to Lecanora pallida have 
rather too large spores for that species. One (63a) has ellipsoid 
spores f n, which I should refer to L. tartarea (L.) Ach.; the other 
