62 
FOURTEENTH REPORT. 
Potentilla anscrina. 
Calamagrostis inexpansa. 
Lysi niach ia t errestris. 
RELIC SPECIES. 
Gin na a non di n acea. 
Iris versicolor. 
Salix long if olia. 
INVADING SPECIES. 
Populus tremuloidcs (seedlings). 
Alnus incana. 
Rosa Carolina. 
Salix hocida. 
Corn us stolonifera. 
Bet ul a alba papyrifcra (seedlings). 
Thuja oocidentalis (seedlings). 
Betula l idea (seedlings). 
Rosa Wanda (near dune bases). 
Pop ul us ha Isa in if era . 
Fraxinus nigra (seedlings). 
The Pyrus-Vacciniuin Thicket Association. 
Invading either the Myrica gale or the Falix-C ornios associations, 
where they occur in bogs or along roadsides, is an association of larger 
shrubs, characterized by Alnus incana and Pyrus arhutifolia. The asso- 
ciation is not typically developt in this region, but it is well suggested 
by the occurrence of these typically dominant species. As far as ex- 
plorations disclosed, there were no species of Vaccmiwm present in 
this association in the region. Farther south Vaccinium is usually 
abundant. This association gives place to the Thuja association which 
it immediately borders. 
List of the Species of the Pyrus- Vaccinium Association : 
DOMINANT SPECIES. 
Pyrus arhutifolia. Pyrus arhutifolia atropurpurea. 
Alnus incana. 
SECONDARY SPECIES. 
Onoclea sensihilis. 
Falix lucida. 
Psedera qu i nquefo lia. 
Corn us circinata. 
L o h e l ia ca rdinal is. 
Carex spp. 
Mentha arvensis canadensis. 
Iris versicolor. 
Eu pa tori um purpureum. 
RELIC SPECIES. 
% 
Evpatorium pcrfoliatum. 
A spidium thclypteris. 
Ly copus a mericanus. 
A quilegia canadensis. 
J) ecod on vert i ci l lata s. 
INVADING SPECIES. 
Fraxinus nigra (seedlings). Thuja occidental is (seedlings). 
Acer ruhrum (seedlings). Ulmus amerioana (seedlings). 
The Elymus Dune Association. 
In many places along the shores of the lakes the limit of ice work 
is indicated by what appear to be a fringing dunes. It is, however, only 
