Bickett—The Larger Aquatic Plants of Lake Mendota. 515 
the plants of the lake may be classified as follows: plants flour¬ 
ishing on sandy soil, Potamogeton pectinatus, P. Bichardsonii, 
Najas, Ranunculus, Chara; plants flourishing on muddy soil, 
Potamogeton zosterifolius, P. amplifolius, P. lucens, Ceratophyl- 
lum, Myriophyllum. Yallisneria and the plant listed as Heter- 
anthera thrive equally well in sand or mud. The remaining plants 
are found in the bays, where the bottom consists chiefly of mud. 
That the substratum is of importance to aquatic plants in ways 
other than merely as an anchorage, is shown by the work of 
Pond (7). 
The Shallow Bays. There are two large and two small bays, 
having distinctive floras. The two small bays, one on either side 
of Governor’s Island, are of the same general nature as Catfish 
Bay, and a study of one of them (station 30) was made as a type 
of all three. The remaining bay (station 4), is of a different 
type. It is shallower, the bottom is composed of mud which is 
not so rich and deep as that of the other bays, and its flora is en¬ 
tirely different. 
The type of flora represented by Catfish Bay consists mainly of 
Potamogeton pectinatus, Yallisneria, and Ceratophyllum, growing 
in a dense, tangled mass, and mixed with a considerable growth 
of both green and blue-green algae. There are in addition sev¬ 
eral patches of Castalia and Scirpus and a fringe of Typha grow¬ 
ing along the shore, as the bay proper merges into a swamp. 
In University Bay are found almost all of the species present 
in the lake. The amount of the commoner submerged forms is 
indicated in the data (table 10), but several species occur only in 
patches, and no account can be given of their abundance, save 
that these plants form a very small percentage of the vegetation 
of the bay as a whole. In this class are Zizania, Nymphaea, 
Lemma minor. Scirpus occurs in a fairly definite strip across the 
bay on the bar, the area of which could be estimated, so that the 
total bulk of this plant could be calculated. University Bay also 
is surrounded by a strip of marsh, where occur several typical 
marsh plants. 
The vegetation in the bays compares more closely with that 
of small, shallow lakes of which ecological studies have been made 
(4), while the great mass of the vegetation of the lake is of an 
entirely different kind. 
Cladophora. The growth of this plant is very varied. In gen¬ 
eral, it is possible to distinguish between three types, as follows: 
