PAPERS OX BOTANY 233 



serotina.) There is little nndergrowtli remaiuing, but in 

 a part of the forest beyond the arbitrary boundary hne 

 are Pnmus virginiana, Podophyllum, Viola, Greranium 

 and Trillium recurvatum. 



In the xerophytic sand ridge forest, the red oaks, 

 Quercus maerocarpa and Quereus alba are the chief 

 ty[Des. The proportions vary but, on the ^rhole, the red 

 oaks are the more common. The shagbark hickory and 

 the black cheriy are also found in smaller numbers and 

 one large black walnut (Juglans nigi-a) stands at the 

 comer of Pine Street and Maple Avenue. Winnetka. The 

 undergro^vth is veiy slight, lacking in shrubs, and con- 

 sists of the more xerophytic hei*bs, as Smilacina rac^mosa, 

 TriUium recurvatum. Viola. Antennaria. Achillea, Fra- 

 garia and PotentiQa. 



The morainic swamp forest, which is the most exten- 

 sive, and also the least disturbed, varies in composition 

 in localized areas, but the swamp white oak (Quercus 

 bicolor) is dominant eveiywhere. Other trees tyi^ical of 

 the swamp forest are the butternut (Juglans cinerea), 

 ebn (Ulmus americana), ash (Fraxinus americana), lin- 

 den (Tilia americana), white maple (Acer saccharinum), 

 and various haws (, Crataegus sp.) although they do not 

 occur in such large numbers. The red oaks and Carya 

 ovata are also members of this forest. The undergrowth 

 is very luxuriant with young trees. Prunus virginiana, 

 Rosa, Sambucus canadensis. Ribes, Rubus. Xanthoxylum 

 americanum. Rhus toxicodendron, Celastrus scandens, 

 Vitis. Ampelopsis quinquefolia. Smilax hispida. Viola sp., 

 Trillium grandiflorum. T, recurvatum, Claytonia, Geran- 

 ium. Phlox. Anemone, Sanguinaria. Cardamine bulbosa, 

 Ranunculus sp. Smilacina racemosa. Podophyllum, 

 Maianthemum, Alliiun, Fragaria. Galiimi, Thalictruni, 

 Osmorrhiza, Iris and others. 



B. DISTEEBrTIOX 



The upland forest is found only in the northwest cor- 

 ner of the region studied, on the morainal till west of the 

 Glenwood bluff. Only small areas appear in this region. 



