JULY, 1902. 
BRUNCKEN — STUDIES IN PLANT DISTRIBUTION. 
149 
As a rule the reclaiming of a heath begins at the foot of a hill, 
so that the lower portion may already show young oak forest, 
while the top is still typical Poa heath. Sometimes it happens that 
the top of the hill is broad and level. It may be either a tilled 
field or a forest. In either case the top may form a base of at- 
tack for the invadmg shrubs (in case of a field, there is usually a 
fence- row, from which they may spread), so that a thicket may 
form both at the foot and the top of the slope, while the middle 
portion is still grassland. 
Mesophytic stations, such as are afforded by the maple-bass- 
wood forests in Milwaukee County, are rather rare in Waukesha. 
Consequently the species characteristic of such localities do not 
form a conspicuous feature of the flora. Such plants as Erythro- 
nhim Ainericanttm, Viola piihescens, Trilliuin grandifioriim, and 
other herbs with very few or no xerophytic adaptations are most 
apt to be found here in moist depressions, where the elm is the 
significant tree. Podophylhim pelfatum has already been men- 
tioned as occurring in the older portions of the thickets described. 
It is rare in the oak forests, except in places where very dense 
underbrush has allowed unusually rich humus to accumulate. It 
is quite common, on the other hand, along fence rows, which here 
as in Milwaukee County are distinguished by a remarkably com- 
prehensive flora. A very interesting occurrence of Podophylhim 
is sometimes found in deep and narrow "kettles," where the forest 
has been cleared or strongly thinned. Here one can sometimes 
find the floor generally covered with grass. In the bottom is an 
accumulation of dry leaves which prevents the grass from grow- 
ing. Here are numerous plants of Podophyllum, which also 
spreads about half way up the southern slope. On the opposite 
side of the kettle, which receives the noon-day sunshine, not a 
single mandrake will be seen, but instead there grow among the 
grass colonies of such xerophytic plants as Antennaria and Viola 
sororia. 
On the whole, it is apparent, that the oak forest has a fair 
prospect of returning to the places from which it was removed, 
when the cycle of heath and thicket is complete. Here and there, 
however, one may observe very dense and old thickets, in which 
the trees are quite absent. This is especially so, where the crab 
apple is the predominant species. As the oak is decidedly intol- 
erant of shade, it may be that the thicket in such cases is too 
dense to allow seedlings to grow up. Another reason, of course, 
mav be simply the absence of seed, as the heavy fruits of oaks 
and hickories do not travel far. One might conceive a case, un- 
der such circumstances, where basswood and maple might find a 
place under the shrubs, as they are certainly tolerant enough of 
