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LICHEN NOTES No. 7. 
Yukon Lichens. 
G. K. Merrill. 
The Lichens enumerated below were collected by Prof. John M.acoun 
during July and August, 1902, in the region around Dawson City, upper 
Yukon. So far as is known this is the first list of these plants for the locality 
In working over the material, there has been found a number of forms new 
to the Alaskan district and a few heretofore unrecorded as occurring in con- 
tinental North America. The collection is remarkable for the abundance of 
its distinctly sub-arctic species, although the district explored is situated 
sixty-four degrees north of the equator. This latitude might well.be expected 
to furnish numerous exclusively arctic forms, but it will be noted that such of 
these as are enumerated were for the most part found on ‘‘the Dome,” a 
mountain four thousand feet in height situated about fifty miles from 
Dawson. No information regarding the climatic conditions prevailing in the 
district is possessed, and comment appended to the names is along other 
lines. Tuckerman’s generic arrangement and sequence of species is adhered 
to, except in Parmelia and Cladonia. 
Cetraria (Ach.) Tuck. 
C. ( Dactylina ) arctica (Hook.) Tuck. With mosses, “the Dome,’’ nos. 
2 and 5. In no 2 attaining to 5 cent, in height, and provided with lateral 
pustular ramuli, while no. 5 is smaller and unbranched. Infertile. Reported 
from various Alaskan localities in most cases maritime. 
r C. ( Eucetrarid ) Islandica (L.) Ach. On humus mixed with other 
lichens. Hunker Creek, nos. 8 and 9, fertile. The margins of the laciniae 
more or less connivent and beset with elongated spinules. Both numbers 
intermediate with var. crisfta. 
C. {Eucetrarid) Richardsonii Hook. On earth, “the Dome;” no. 13, 
infertile. The identification made positive through comparison with Rich- 
ardson's specimens, by kindness of Prof. W. G. Farlow. Not previously 
reported from the Alaskan region. 
C. {Eucetrarid) cucullata (Bell.) Ach. On humus, “ the Dome,” no. 6 
infertile. Hue Lich. Ex. Eur. i, p. 85 reassociates this species with Cetraria. 
Its affinities are clearly with that section which shall include C. Islandica , 
for not only does the latter furnish forms distinctly similar in lobation, but 
C. cucullata is in high latitudes sometimes found with spinulose margins. 
This condition is noted in the present number. 
C. {Eucetraria) nivalis (L.) Ach. On humus, Mt. Moosehead near 
Dawson, no. 7, infertile. Hue also reaffirms this species to Cetraria. Ex- 
cellent reasons for this view may be found in West Greenland Lichens, Lind- 
say, Trans. Linn. Soc. vol. XXVII, 1869, p. 322. 
C. {Platysma) Fahlunensis (L.) Schaer. On rocks, Hunker Creek, 
nos. 35 and 36; Bonanza Creek, no. 11; and “the Dome,” no. 12. All fertile 
but no. 35. 
