224 THE PLANT WOKLD 



course of the stream. There was welcome evidence of much more 

 moisture throughout this region ; the woods are marked by larger size 

 and greater abundance of trees, and by more ferns and mosses. 



Professor MacBride, who listed the trees of Allamakee County, 

 names forty-three trees and shrubs, all of which, with two or three 

 exceptions, we found in our brief exploration along the Yellow River. 

 The Quercus Mulilenhergii, a tree belonging further south, is found here. 

 At the point where the road strikes the stream, the valley is per- 

 haps a mile wide, with bluffs precipitous and canon like. The valley, 

 before the windings of the bluff-line cut off the view, extends several 

 miles east and west. This little piece of the " Switzerland of Iowa," 

 here on the borders of the prairie, deserves its name, and with the sun- 

 rise and sunset to add to its charm, is certainly a beautiful spot. All 

 through that part of the country the private groves of evergreens are so 

 numerous and thrifty, that it was not a matter of surprise to find that 

 Nature had set the example by a plentiful sprinkling of evergreens in 

 the woods along the stream. Following the south bank of the stream 

 going east, we come at once upon the Taxus Canadensis growing freely 

 upon the limestone bluffs ; here also some rock-loving ferns. About 

 eighteen of the twenty or more different ferns of the state are found in 

 this county, among them one fern usually more abundant in more 

 southern regions, the beautiful Phegopteris hexagonoptera. Further down 

 the stream, amongst the rocks of the steep hillside, is a heavy, fresh 

 growth of Taxus with its red fruit, mosses, lichens and ferns holding 

 considerable moisture even in August. Here the paper birch (Betula 

 papyri/era) and balsam fir (Abies halsamea) are the principal trees; in 

 the immediate neighborhood are the staghorn sumac {Rhus typliina), the 

 purple trillium, Jack-in-the-pulpit and occasionally the ginseng, with 

 its tiny crown of red-brown fruit. The firs grow not too closely, 

 mingled with birches as they are, to assume very perfect form. 



Along the northern side of the valley the prairie encroaches much 

 closer ; along the bluffs stand frequent pines, some very tall, far over- 

 towering the valley. Their position is very much exposed to winter 

 storms and summer heat, and they are somewhat weather-worn. These 

 bluffs are clothed with grasses, and all along the ledges springs the 

 cedar, Jimiperus Virginiana. These bluffs are much more affected by 

 the dryness of the summer than is the opposite side. 



Two miles further down stream the current has cut its way into St. 

 Peter's sandstone; whilst nearer the mouth the Oneota limestone is 

 exposed, thus enlarging the variety of conditions in this region. Other 

 trees than those already named, of unusual occurrence for Iowa, are 

 mentioned by Professor MacBride as follows : Ahius incanus, Betula 

 lenta, Morus rubra and Acer spicatum. As in our own woods of central 



