332 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



serotina and Liquidambar styraciflua. Sphagnum often covers the 

 ground. The undergrowth varies in different places. The most 

 prominent constituents are small plants of Pinus serotina and Liquid- 

 ambar styraciflua, Ilex glabra, Drosera longifolia, Limodorum tuber- 

 osum, Rhexia mariana, Blephariglottis cristata, Magnolia virginiana, 

 Lycopodium alopecuroides, Lycopodium adpressum, Persea pubescens, 

 Arundinaria tecta, Viola sp., Xyris, and some of the sedges of the 

 lake. The trees are often festooned with Dendropogon usneoides or 

 covered with lichens. 



ALGAL FLORA. 



The algal flora of Lake Ellis is rich in number both of species and of 

 individuals. The great mass of plants growing in the lake gives a 

 large surface for attached forms. All of the submerged plants and 

 the stems and the under surface of the floating leaves are covered 

 with these. The filamentous forms growing on these surfaces and 

 the submerged plants themselves form habitats for diatoms and 

 desmids, which occur in great numbers. 



The green algae are present in great abundance, but do not at this 

 season form dense masses and do not seem to be in a vigorous condi- 

 tion. The blue green algse are even more abundant than the green 

 algae and seem to be in better condition. This seems to agree with 

 the conclusions of Fritsch (1907) that the blue greens are better able 

 to endure a high temperature than the green algse. 



The conditions for algal growth are fairly uniform over the whole 

 lake, and the distribution of the species is fairly general. 



Besides the algas, there are large numbers of bacteria, especially 

 at the surface. 



The following is a list of the principal algse found in Lake Ellis: 



Anabaena Jlosaquae (Bg.) Kg. 

 Batrachospermum monibifurme Roth. 

 Bulbochaete sp. 

 Chantransta sp. 

 Hapalosiphon brebissonii Bg. 

 Lyngbia sp. 

 Merismopedia glauca Bg. 



Ocdogonium sp. 



Spirogyra insignis (Hass.) Kg. 



Spirogyra sp. 



Ulothrix sp. 



Zygnema purpureum AYolle. 



Zygnema sp. 



GREAT IAKE. 

 PHYSICAL CHARACTERS. 



Great Lake lies to the west of Lake Ellis. It is kidney-shaped, and 

 about 4| miles long by 3$ wide in the widest part, with an area of 

 about 3,000 acres. In the center of the lake the water is about 8 feet 

 deepT 



The lake has no inlet, but the water comes from the surrounding 

 country, which is partly swampy. Owing to the flatness of this 

 country; the porousness of the soil, and the dense growth with wliich 



