380 IOWA ACADEIVrY OF SCIENCE Vol. XXV, 1918 



The representative species are : 



Panicum Scrihnerimium, Panicum virgatiim, Fragaria vir- 

 giniana var. illinoe^isis, Senecio aureus, Anemone canadensis, 

 Viola cucuUMa, Hypoxis hirsiita. 



D. Consocies Leersia. 



Location : Wet, low ground. 



Soil : Loam to clay loam. 



Arrangement : Gregarious. 



The prominent species are : 



Leersia oryzoides, Anemone canadensis, Pliysotegia virgin- 

 iana, MuJilenhergia racemosa. Polygonum Muhlenhergii, Apo- 

 cynum cannahinum 



III. Swamp Location : Standing water present a part of the 

 year. 



TypJia-Juncus-Penthorum Formation, 

 Soil : Loam to clay loam. 

 Arrangement: Aggregate zoned. 



A. Consocies Typlia-Juncus. 

 The principal species are : 



J uncus tenuis, Cyperus sp., Typlia lati folia, Alisma plan- 

 tag o-aquutica, Sagittaria latifolia. Polygonum 3Iuhlenhergii, 

 Leersia cnifzoides, Calamagrostis canadensis, Eupatoriuni, 

 Asclepias purpnrenm var. m-acidatum,. 



B. Consocies : Penthorum. 



The more common species are : 



Penthorum sedoides. Polygonum liydropiper, Polygonum 

 acre, Lippia lanceolata, Steironema lanceolata, Stachys palus- 

 tris, Epilohium coloratum, Lohelia siphilitica, Bidens cernua. 



C. Consocies Ludwigia-Spargamiim. 

 The outstanding species are : 



Juncus tenuis, Scirpus lacustris, Iris versicolor, Penthorum 

 sedoides, Calamagrostis canadensis, Ludwigia pohi.carpa, Spar- 

 ganium e urycarpum. 



D. Consocies : Leersia. 

 IV Pond 



Ranunculus-Sagittaria Formation. "Water present most of 

 the time. 



Arrangement: Gregarious, copious, zoned. 

 A. Consocies h'anunculus. 



Ranunculus del /)Jii)ilfoUus, Alisma plantago-acjuatica. 



