114 PUBLIC PARKS OF IOWA 



since to my knowledge the species does not occur in the vicinity of Web- 

 ster City along the Boone river. The occurrence of the cherry birch in 

 the vicinity of Steamboat Rock is another equally interesting discovery. 

 So far as I know this is one of the few recorded localities in the state. The 

 cherry birch is a distinctly northern tree, found in moist, sandy, rocky 

 soil in western Wisconsin. The white birch occurs in the more exposed 

 and drier places, conforming to its habitat, in western Wisconsin and 

 northeastern Iowa, as I indicated in a paper in Garden and Forest on the 

 forest vegetation of the Upper Mississippi. MacBride*, in his paper on 

 the forest trees of Allamakee county, says: "Certainly confined to the 

 northeast corner of the state." 



Until finding the species last fall I had not known of its occurrence in 

 Iowa except in the counties north of Dubuque along the Mississippi river. 



The flora of this region is a typical northern or, more properly, the 

 transition of C. Hart Merriam.* 



The arboreal vegetation is accompanied by many typical northern 

 species. It has many more northern species than Clinton or Dubuque 

 counties and but few of their southern species. Papaw (Asimina triloba), 

 pignut (Carya olivaefornis), Cercis canadensis, and Q. acuminata 

 occur at Clinton but are entirely wanting near Steamboat Rock. The 

 typical transition species occur for some four or five miles north of Steam- 

 boat Rock but disappear south. These are practically confined to the 

 sandstone ledges. Beyond these ledges the timber presents nothing un- 

 usual for central Iowa. 



This small area is well watered and where it was not pastured it was 

 decidedly swampy, as evidenced by the profuse growth of jewel weed 

 (Impatiens fulva), and greater lobelia (Lobelia syphiltica). The showy 

 lady slipper (Cypripendium spectabile) was less common in open places. 

 In the densely shaded woods the ground was covered with a species of 

 hypnum. Ferns (Phegopteris dryopteris, P. polypodiodes, Asplenium 

 felix-foemina, Polypodium vulgare and Aspidium marginale). The lat- 

 ter to my knowledge has not been recorded for the state, and certainly 

 is much beyond the usual range given to it. In Wildcat Den, Muscatine 

 county, where the physical conditions are somewhat similar, it is entirely 

 absent. The two species of ferns (Phegopteris) have been reported from 

 other sections of the state. All of these are northern species. The small 

 bush honeysuckle (Diervilla trifida) has a range from Newfoundland to 

 mountains of North Carolina west to Minnesota. Reppert also reports 

 it from Muscatine county. It is, therefore, much beyond its usually given 

 range. The silky cornel, (Cornus circinata) is a common shrub on sandy 

 rocks in western Wisconsin, its natural range being from Nova Scotia to 

 Dakota, south to Virginia and Missouri. Its Missouri occurrence is like 

 the Iowa, usually in isolated places. Reppert records it from Muscatine 

 county along Sweetland creek and I have observed it as a rare shrub at 

 the ledges in Boone county. The dogwood (Cornus asperifolia) is more 

 common. The sandy piny woods are covered with oat grass (Danthonia 

 spicata), which is true also of the woods along Pine creek in Muscatine 

 county and the carboniferous sandstone ledges in Boone county. 



'Year Book U. S. Dept. of Agri., 1894, p. 209. 



