I 44 
CUMMINGS 
east Cape (Coville and Kearney, 200S) ; Port Clarence (Trelease, 
1254, 1112, the latter a fragment mixed with Partnelia saxatilis, 
Par melia physodcs and Alectoria diver gens) ; Cape Nome (Setch- 
ell). All specimens sterile. Collected at Taku by Dr. Ilayes, and 
on St. Paul Island by J. M. Macoun; Hooker and Arnott report its 
occurrence at Kotzebue Sound, and Babington credits it to the same 
locality. Nylander lists Platysma cucullata Hoffrn. as occurring at 
Port Clarence. 
This species is distributed from about latitude 40° N. to the Arctic 
regions, both in the Old and New Worlds. 
211. Cetraria islandica (L.) Ach. 
Lichen islandicus Linnaeus, FI. Suec. 1085. 1755. 
Cetraria islandica Acharius, Meth. Lich. 293. 1803.— Sowerby, Eng. Bot. 
t. 1330. — Nyl. Syn. t. 8. f. 32. 
Summit of White Pass (Trelease, 1193) ; Kadiak (Trelease, 1194, 
1194a, 1194*5), mixed with Alectoria and Cladonia; Unalaska (Set- 
chell) ; Hall Island (Trelease, no number) ; St. Matthew Island (Co¬ 
ville and Kearney, 2113) ; St. Lawrence Island (Trelease, 1206) ; Port 
Clarence (Trelease, 1198, 1207); St. Michael (Setchell) ; Cape 
Nome (Setchell). Babington reports its occurrence at Norton Sound 
and Kotzebue Sound ; Hooker and Arnott credit it to the latter locality. 
J. M. Macoun collected it on St. Paul and St. George Islands, the 
forms gracilis and robustus growing with the type. Also collected 
on Seward Peninsula by Arthur J. Collier. 
This is a very variable species, and the transition forms between the 
species and its varieties are very puzzling. No. 1207 may be consid¬ 
ered one of the most typical forms, though these specimens are some¬ 
what lighter than is normal. The thallus grows nearly upright, 
branching freely. The fibrils on the edge of the lobes of the thallus 
are short and unbranched. The specimen from Port Clarence (no. 
1198) is much abbreviated, and in the broadening of its shining lobes 
tends toward the variety platyna . The most interesting variation, 
however, is in the specimens from the summit of White Pass (no. 
1193) and from Kadiak Island (no. 1194a). In these specimens the 
lobes are long, narrow, and flexuous, thickly beset on the edge with 
long fibrils, which in the specimen from White Pass are variously 
branched. Dr. Lindsay, in West Greenland Lichens, 321, suggests 
that this state “might appropriately bear the name (if name is re¬ 
quired) of form or variety leucomeloides ” because of its resemblance 
to Physcia leucomela. All these specimens are sterile. 
