Baker—The Fauna of The Lake Winnebago Region. 125 
The aquatic flora may be divided broadly into two groups, 
emergent and submerged. These may be differentiated as follows: 
Emergent 
Submerged 
Zizania aquatica 
Scirpus validus 
Scirpus occidentalis 
Castalia odorata 
Nymphaea advena 
Lemna trisulca 
Potamogeton natans 
Vallisneria spiralis 
Elodea canadensis 
Ceratophyllum demersum 
Myriophyllum verticillatum 
Potamogeton pectinatus 
Potamogeton richardsoni 
Potamogeton zosterifolius 
Potamogetom lucens 
Chara 
Cladophora 
No attempt was made to obtain a list of all the species of aquatic 
plants, only the common and conspicuous ones being included. The 
lake offers a wide field for botanists and a complete list of the flora 
would be quite extensive. 
Animal life was four times as abundant in vegetation as on the 
sand bottom areas, which was the richest region of the bottom 
areas. The number of species represented, however, was not as 
great (sand 40, vegetation 25). Among mollusks, four species 
make up 91 per cent of the total population, Amnicola limosa 
porata 21 per cent, Valvata tricarinata 48 per cent, Physa sayii 13 
per cent, and Planorhis parvus 9 per cent. Among associated ani¬ 
mals, which are more than four times as abundant in individuals 
as the mollusks, three groups make up 87 per cent of the entire 
population; Hyalella knickerhockeri 41 per cent, Chironomid 
larvae 31 per cent and Oligachaete worms 15 per cent. 
Several animals prefer certain species of plants as a habitat. 
Thus the broad leaves of Nymphaea and Castalia, principally on 
the under side, are tenanted by Physa sayii, Planorhis parvus, 
Pldnorhis antrosus, Planorbis campanulatus, Amnicola limosa 
porata, Amnicola walkeri, Valvata tricarinata, young Bythinia 
tentaculata, and Lymnaea winnebagoensis. Among associated ani¬ 
mals such species as Donacia proxima, Planaria maculata, the 
larvae of Nymphula, and the eggs of Donacia and Gyrinus are 
common. Some Hyalella are always found on these leaves. Scirpus 
is the natural home of Ferrissia parallela and Bythinia tentaculata. 
