26 MICHIGAN SURVEY, 1908. 



berry, Sarsaparilla (dominant), and Clintonia horealis. but Aster 

 maorophi/llus was not as abundant here as elsewhere. The larger 

 Birches averaged about 12 to 15 inches in diameter. The general 

 appearance of the conditions is shown in Fig. 39. This patch of birches 

 was near the swamp (V, 5). From this Birch colony, on to the end 

 of the trail to Siskowit Lake, the forest was dominated by large Birch, 

 with a. few quaking Aspen, Balsam and White Spruce, while in the 

 damper places Ground Hemlock and Dogwood were abundant. On 

 the ridges there are small "islands" of Cladonia, mosses, Bearberry and 

 a ground pine. The general appearance of this forest, in an open place, 

 is shown in Fig. 40. 



While there Are thus minor differences which prevent absolute homo- 

 geneity in the general conditions of the forest, yet these differences do 

 not seem to particularly influence the environment as a whole. The 

 general transition from the openings, as found on rock ridges like those 

 about camp (V, 3), to the Balsam-Spruce forest may be seen by a com- 

 parison of Figures 25, 26. 27 and 38. 



The fauna of the forest (V, 4) is rather varied. The shells are repre- 

 sented by Acanthinula harpa, Zonitoides ariorea, and PyramidAda 

 cronkheitei anthoni/i; the beetles by the carabid, Calathus, the fungus- 

 inhabiting beetles, Boletdbius, Tritoma and Grophaena, and doubtless 

 many of the other species which were taken about the flowers and the 

 camp. The wood-boring Hymenoptera, as XJrocerus, are also character- 

 istic of this kind of forest. Hares remained concealed in the forest^ 

 during the day, but at dusk they came in large numbers into the clear- 

 ings to feed. The birds had begun to migrate when this location was 

 examined, so that little attention was given to their habitat preferences. 



Station, Y, Substation 5. Tamarack Swamp. This swamp lies between 

 Siskowit Lake and the western end of the trail through the Balsam- 

 Spruce forest (V, 4). This is a valley swamp bordering a small stream 

 which flows through the swamp. The central open part of the swamp 

 is occupied by a small pool or pond, Fig. 41, which is invaded by Yellow 

 Waterlilies. Surrounding this is a zone of Buckbean and sedge, the 

 overgrowing sedge being more conspicuous. This sedge zone is quite 

 wet and quaking. The current of the stream passed through this zone 

 and parted the sedges in a wet line two or three inches wide. At its 

 outer border, the zone becomes invaded by small Tamaracks, 4 to 5 

 feet high, alders, willow, scattered Cassandra and Pitcher Plants, and 

 Wild Eosemary (common). Eriophormn, the Blue Flag and the Purple 

 Cinquefoil occur in some of the depressions. A very few small Arbor 

 Vitae also occur here. A strip of trees bordered the stream, while 

 farther south occurred the Cassandra and Sphagnum zone proper. The 

 latter contained scattered Blue Flags, and upon dry hummocks, colonies 

 of Cladonia, which seemed rather out of place. The margin of this 

 area was invaded by the Tamarack, Black Spruce and Labrador Tea. 

 The general appearance of this forest is shown in Figs. 42-43. Near the 

 margin of the swamp, where the spruces are quite large and the ground 

 well shaded, the growth of Labrador Tea and Sphagnum was very lux- 

 uriant. The growth of Sphagnum at this place was by far the most 

 luxuriant seen upon the island. It grew in hillocks over fallen trees 

 and stumps, and stood considerably above the general level of the swamp. 



