re a nN N50 
ee Se 
1899] ¢ 
DUNE FLORAS OF LAKE MICHIGAN 
379 
. . l | 1 f 
a 3. The oak dunes. 
e south 
as Manistee, Des of the lake, and as far up the eastern shore 
father open and may be seen old dunes covered over with 
been established cee oak forests. These dunes have lon 
laden winds Be ee entirely free from the destructive Panic 
of the other du mee influential in determining the character 
and are Be ssted Hope As a rule the oak dunes are low 
rom the lak : 
which ; e lake by se 
~~ vegetation eae y several series of dunes on 
e domina we 
I soccinei .. = on the oak dunes is the black oak, Quer- 
ria This tree is far more abundant than all 
et others combi 
"acteristic Ve . The only other tree that may be called char- 
Be there ac “ Park region is Quercus alba. On some oak 
ow trees or tall shrubs of Sassafras officinale, 
Cornus flori 
The  eeeeaniaas Canadensis, and Hamamelts Virginiana. 
OWer margins e shrubs are comparatively few except along the 
slopes. The mo ward the swamp level, or on shaded northern 
if Pennsylvani ids abundant shrubs are Vaccinium vacillans and 
a —. Salix humilis, Viburnum acerifolium, Rosa 
The er and Rhus copallina. 
fied and Sas vegetation of the oak dunes is very diversi- 
Permit an . The trees are always far enough apart to 
On the ether: ve undergrowth of relatively light-loving plants. 
the sun, there % slopes, where there is considerable exposure to 
less tufted a rareay a continuous vegetation carpet, but a more 
tee number tees with intervening patches of naked sand. 
xample : cs herbs are characteristic of such places, for 
Bae —  Koeleria cristata, Cyperus Schweinitst, 
"ginica, Arabis a, C. umbellata, C. Muhlenbergi, T) radescantia 
lyrata, Lupinus perennts, Ts ephrosia Virginiana, Les- 
commonly in neighbor- 
5 The 
: close] 
i 
re Sg . Quercus rubra and Q. coccinea occur 
m be an 
fee forms here m Hass im present on the dunes, as may hybrids tween any of 
