All Ecological Study of Buckeye Lake. 21 



rosa. Xelumbo lutea is also often associated with Castalia 

 tuberosa. There are several large tussocks of Typha angusti- 

 folia at a depth of two and one-half to three and one-half feet. 

 These are always pure societies except that at the margin of the 

 tussocks are generally a few Castalia, Nelumbo, Potamogeton 

 or even Nymphaea advena leaves. In the center of the tussock 

 are no other plants. Not as numerous but alternating with the 

 Typha angustifolia are tussocks of Typha latifolia. This latter 

 species grows in somewhat shallower water, water at a depth of 

 one and one-half to two and one-half feet. It never seems to 

 occur as a pure society, but it always associated with Spar- 

 ganium eurycarpum, Polygonum emersum and often with 

 Hibiscus moscheutos and Scirpus fluviatilis. Bidens species are 

 often growing on the uprooted masses or even on the sediment 

 covered bases of the living stalks. 



The two associations here represented, that of fixed aquatics 

 with floating or submerged leaves and that of a reed marsh, do 

 not exhibit a well defined zonal arrangement, except where they 

 border an island, Buckeye Point or the shore of the cove. Then 

 either a pure Nelumbo society or a Nelumbo-Polygonum emer- 

 sum society forms the outer zone in water varying in depth 

 from 5 to 2^ feet. This is followed by a Polygonum zone or a 

 Polygonum-Potamogeton or by a Typha zone. The Typha zone 

 in some cases, extends to the exposed shore line; in others there 

 is a Typha-Scirpus, or Typha-Hibiscus followed by a shrub 

 zone. The shrub zone is generally but poorly represented. In 

 the open water the associations exhibit an alternation. Depth of 

 water and wind exposure have some influence on the position of 

 the societies. Typha angustifolia grows in deeper water than 

 T. latifolia; Nelumbo lutea and Castalia tuberosa grow in deeper 

 water than Nymphaea advena. Potamogeton lonchites and P. 

 pectinatus grow in deeper water and where wind exposure is 

 greater than P. zosterifolius and P. pusillus. All the Potamoge- 

 ton grow more luxuriantly to the lee of an island and of Typha 

 masses than on the windward side. Polygonum emersum is 

 gregarious. It grows in water 5^ feet deep and also in the mud 



