ECOLOGICAL STUDY OF BRUSH LAKE. 157 
side the wide, shallow, artificial area of water corresponding to 
this zone is mostly covered with Chara sp., various pond weeds, 
Batrachium divaricatum (Schr.) Wimm., and Zannichellia 
palustris L. 
An interesting plant also is Cicuta bulbifera L., which is 
covered in the fall with little bulbs. These drop off and float 
around on the surface of the water. Although found in several 
places this plant does not seem able to hold much ground consid- 
ering the great advantage it has of being distributed into every 
favorable nook and corner by means of its brood buds. Eleocharis 
palustris (L.) R. & S. and Scirpus lacustris L,. are also promi- 
nent in this zone. The floating plants of the water-lily zone are 
abundant, as would be expected. Other plants which are present 
are as follows: 
Roripa palustris (L.) Bess. 
Naumbergia thyrsiflora (I,.) Duby. 
Scutellaria lateriflora L. 
3idens cernua L,. 
Polygonum punctatum Ell. 
Alisma plantago L. 
Sagittaria latifolia Willd. 
4. DECODON ZONE. ‘This is one of the most remarkable 
societies surrounding the lake. It is a Decodon-Solanum dul- 
camara zone. The characteristic plant, which in many placcs 
forms almost a pure society, is the tall crownformer, Decodon 
verticillatus (L.) Ell. The twining bittersweet, Solanum dul- 
camara L,., is also very prominent. Some of these plants develop 
as floating individuals, having no connection with the ground, 
but developing numerous water roots along the submerged part 
of the stem. This zone is 30 feet wide at the north end. It 
begins in water from one to one-half foot deep and ends at the 
outer edge in water of about three or four inches, or even beyond 
the water’s edge. At the north end it is limited on the outside 
by the shrub zone which extends to the edge of the water or 
beyond. The tali shoots of the Decodon, many of which are 
fasciated, form a tangled mass through which it is very difficult 
to pass both when they are green and in winter when dry. ‘The 
Decodon is especially well adapted for holding air in the cortical 
layer of the much branded base and is thus well fitted to carry on 
