JANUARY, 1902. BRUNCKEN STUDIES IN PLANT DISTRIBUTION. 
23 
been favored. This has occurred where the culling has been mod- 
erate, so that the shade on the floor remained too dense to allow 
the growth of the intolerant oaks. Thus there is a considerable 
tract in the town of Wauwatosa, which is now an almost pure 
maple wood with the young trees ranging in age from the last 
year's seedling up to good-sized poles. The few standards re- 
maining are in about equal numbers oaks and maples, but oak 
seedlings are entirely absent. The floor is almost bare of vegeta- 
tion and the humus deep and rich. Similar places are found 
scattered in many parts of the country. 
It was stated in the beginning of this article that there was 
evidence of this region having been clothed at one time with a 
xerophytic forest, mostly composed of conifers. This proposition 
remains to be discussed. 
A glance at the vegetation map shows that to the north of 
Milwaukee County the Oak and Oak and Maple Groups are re- 
placed by two quite dissimilar types of forest. In one of these 
the white pine is prevalent; this group stretches along the Lake 
Shore in a strip that gradually narrows as it comes South. The 
other type is characterized by the prevalence of hard maple, yellow 
birch and hemlock, and the almost complete absence of oak. This 
is the association which covers such large areas in the central part 
of Northern Wisconsin (4). Of both these associations relicts 
are not infrequently found in the neighborhood of Milwaukee, 
thus indicating that they must once have been represented in 
this region. 
The white pine association has for its most characteristic com- 
panion tree the paper birch. This tree is still common in a very 
narrow strip along the shore of Lake Michigan. The white pine 
itself formerly occurred in the same narrow strip, but the last large 
specimens seem to have disappeared a few^ years ago. It is said 
that a few very small individuals are still growing in a ravine 
near Fox Point. Going south, from Milwaukee, the white pine 
re-occurs on sandy beaches and on the dunes near Chicago. The 
paper birch is very well developed in several places along the 
Lake Shore, to the South, conspicuously so on the broad and 
swampy land flat north of Waukegan, Ills. Small species usually 
accompanying this association, such as Pteris aquilina, are found 
sparingly in the paper birch strip, although they are entirely absent 
everywhere else in our territory. The conclusion can hardly be 
avoided that the white pine areas of the North and the Southern 
(4) See Roth, Forest Conditions of Northern Wisconsin. 
