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FOURTEENTH REPORT. 
6. The fundamental starting point for genetic series is the waters 
of the different lakes of the region. The lines of succession commence 
with open water and procede thru stages of progressivly increasing 
dryness and progressivly increasing humification, reaching the ultimate 
climax in the Beech-Maple association. The intermediate steps group 
themselves along five genetic lines. 
7. Commencing with the lake one genetic series extends from aquatic 
algae thru associations living in shallower and shallower water to the 
edge of the water. The swamp series whose associations replace open 
water by a swamp area, normally of but brief duration. The bog series, 
which converts open water into a plant covered area and precedes thru 
associations of higher growth-form in richer soil until the tract is tree 
covered. The sandy-laml series, whose associations advance in growth- 
form and live in progressivly richer soil. The burn series brought 
about by accidents interrupting the normal genetic series resulting in 
rejuvenescence. 
8. Under present climatic and soil conditions there are three quasi- 
climatic associations which should occupy virtually the entire area: on 
the bog land, fhe Thuja association; on the dry sandy land, the pine 
association ; and on the richer sandy or clayey land, the Beech-Maple asso- 
ciation. As the result of burns, lumbering, etc., a great deal of the land 
is occupied by the aspen association, tending, however, to be replaced 
by the normal associations for the kind of soil. 
0. Between the three qua. si-climatic associations mentioned above 
there is nearly a stable equilibrium with the following tendencies with 
obtain either way. The drying of bog land permits pine or hardwood 
invasion and the humification of pine land permits hardwood invasion. 
EXPLANATION OF PLATES. 
Plate. 
Map of the region in the vicinity of Douglas Lake, Michigan 1. 
Diagram illustrating the successions shown by the associations. . 2. 
Meteorological data of the general region, part 1 3. 
Meteorological data of the general region, part II 4. 
A general view of the aspens north of Burt Lake 5. 
A view on Maple Biver 6a. 
A view in North Fishtail Bay showing Potamogetons 6b. 
The mouth of Bessey Creek showing the Scirpus validus associa- 
tion 7a. 
The Salix-Cornus association in burnt-over boglaml 7b. 
Silver Lake 8. 
An Elymus dune along Douglas Lake 9. 
Pinus strobus seedlings in the aspen association 10a. 
Cedar and spruce nearly topping the tamaracks 10b. 
A general view of Beese's Bog 11. 
An interior view in Beese’s Bog 12. 
An interior view in a cedar bog; a lumber road 13a. 
The west shore of Burt Lake showing hardwoods 13b. 
An open spot in a cedar bog showing Chiogenes liispidula 14. 
