208 



meters high. In the center of one of these thickets were plants 

 of Mentha arvensis canadensis and Chelone glabra, over two meters 

 high, whose exceptionally slender stems were supported by the 

 surrounding Decodon. 



Bordering the Berula association on the side away from the 

 springs and along the creeks just beyond the running water, 

 the Saururus association has developed. This association is 

 composed of exceptionally well-developed plants of Saururus 

 cernuus, growing somewhat more than a meter high, with large 

 leaves, many long flowering spikes and numerous seeds. With 

 the 5a2^fM;'W5 were virtually no other plants. (Fig. i.) 



Bordering the narrow strip of Saururus was a somewhat wider 

 strip of thicket plants, most important of which were Salix 

 longifolia, Cephala?ithus occidentalis, Cornus amomum and Rosa 

 Carolina. In any given spot one of these usually grows to the 

 exclusion of the others, but all of them occupy the same relative 

 position in the vegetation. Cephalanthus and Cornus occur more 

 abundantly on the springy boggy soil nearer the headwaters of 

 the little creeks, while the Salix is very much more abundant 

 nearer Lake Matanzas and along the nearby Illinois river. 

 Thicket plants occur over nearly the entire area but they produce 

 their characteristic appearance only near the creeks, for else- 

 where trees are rapidly assuming dominance. Usually the ground 

 is bare of plants and consists of muck together with the debris 

 which the lower sprawling stems of the bushes have sifted from 

 the flood waters of the Illinois river. A sparse growth of herba- 

 ceous plants may be present in openings which admit sufficient 

 light to reach the ground. Most important of such species are 

 Asclepias incarnata, Boehmeria cylindrica, Peltandra virginica, 

 Apios tuberosa, Cicuta m-aculata, Iris versicolor, Steironema cilia- 

 turn, Ranunculus abortivus, Pilea pumila, Eupatorium perfolia- 

 tum, Lippia lanceolata, Verbena hastata, and in addition, seedlings 

 of Betula nigra, Acer saccharinum, Fraxinus nigra and Fraxinus 

 americana may also be present. 



The greater part of the bog is covered by the bottomland 

 woods. Although the usual bottomland trees are present, the 

 association does not appear normal as it has not yet become 



