52 
FOURTEENTH REPORT. 
ly indicated by the gradual grading of the Eleocharis into the Scirpus 
umericanus as the water became shallower. 
List of the Species of the Eleocharis Association : 
DOMINANT SPECIES. 
Eleocharis palustris vigens. 
U tricu lav i a cor nut a . 
Glyceria borealis. 
Nymp ha ea am erica n a. 
Lycop us amcrica n us. 
Solidago gra minifolia. 
Scirpus americamis. 
Iris versicolor. 
8 pari ina michauxiana. 
Lobelia cardinulis. 
SECONDARY SPECIES. 
Veronica a na ga llis-a quatica. 
Oxypolis rigidior. 
RELIC SPECIES. 
Sag it tar ii i la ti folia. 
INVADING SPECIES. 
Mentha arvensis canadensis. 
Mi mu lus r ingen s. 
Eotentilla palustris. 
Acer rubrum (seedlings). 
Cor mi s stolonifera (seedlings). 
8alix lucida (seedlings). 
The Scirpus valid us Association. 
This association of aquatic plants, rooted below the surface of the 
water but extending above the water, appears to be the most extensive- 
ly represented aquatic association, altho the Chara association really 
is so. It occupies submerged land from water level down to water about 
8 feet in depth. In Douglas Lake it is limited to the shoals and the 
shores of bays and inlets, especially towards the west where the lake 
is more protected from the prevailing winds. Except at the mouth of 
Bessey Creek, this association occurs in patches which are not very 
dense, and yet there are virtually no secondary species. At the mouth 
of Bessey Creek is a very dense growth of this association, shown in 
Plate 7a. In places in it, the way has been paved for a considerably 
higher association in the genetic series and such plants as Decodon 
verticillatus , Eupatorium perfoliatum , Eupatorium purpureum, Lobelia 
cardinaUs, Asclepias incamata, Salix lucida and Sagittaria latifolia are 
now present. 
Normally this association is succeeded by the Scirpus americamis as- 
sociation, but during 1911, in the unusually high stages, following the 
heavy spring rains, the Scirpus valklus association gave decided evidence 
of invading the Scirpus americanus association , in which the Scirpus 
validus is usually present as a relic. The extreme openness of the aquatic 
vegetation materially aided this invasion, which is a reversal of the 
normal line of succession. 
