BIG SPRING PRAIRIE. 59 



bog formations. It is a Hydro-mesophytic Society, and 

 can best be designated as a Potentilla fruticosa, Betula 

 pumila, Salix myrtilloides, Rhus vernix heath. The 

 last three species are the characteristic and common 

 plants of Sphagnum swamps, either the simple Sphag- 

 num swamp such as occurs at Fox Lake, Wayne Co., 

 Ohio, or the Tamarack Bog as the one on the Calumet 

 flood plain at Millers, Ind. 



It is still an unsolved problem whether these spec- 

 ies are remnants of a former Sphagnum swamp, or 

 whether they are ever associated together on areas 

 where Sphagnum moss has never occurred. 



Big Spring Prairie marks the southern limit for 

 the range of Betula pumila in Ohio. Besides the Salix 

 myrtilloides, there also occurs Salix Candida, Salix beb- 

 biana, and Salix lucida. The Salix Candida is the next 

 most common species to Salix myrtilloides. Close to 

 the shallow old ditch along the western margin there 

 occur occasional large willows and poplars. In some 

 portions the Potentilla fruticosa predominates as in 

 field just south of the divide, while at others there are 

 various combinations of the remaining characteristic 

 species. The remaining shrubby plants are Rosa Caro- 

 lina, Cornus stolonifera, and Ribes floridus, the last the 

 least abundant. 



The principle grasses and sedges are Chrysopogon 

 avenaceus (Michx.) Benth. (Indian Grass); Phragmites, 

 (Reed); and Carex (various species). 



The principle herbaceous plants are Solidago rid- 

 dellii (Riddells Goldenrod); Solidago ohioensis (Ohio 

 goldenrod); Allium cernuum (Nodding Onion); Lacin- 

 aria spicata (Gay feather Devils-bit) and Dryopteris 

 thelypteris (Marsh Shield Fern.) In fig. 11, the Solid- 

 agos are shown to the left of the ditch chiefly. 



The Allium and Lacinaria in field in vicinity of 

 Ox Spring were found to be by far the most abundant 

 on the marly streaks and areas; they occur much less 



