THE PLANT WORLD 223 



rare in the State. Among the ferns Aspidium marginale is common, a 

 very rare fern in Iowa, The graceful Cystopteris hidhifera and mosses 

 climb the cliffs where they find moisture and foothold ; above them 

 Folypodimn vidgare and lichens are doing their share toward modifying 

 the surface of the rock. 



In many shaded and damp places Impatiens julva is growing vig- 

 orously. In a marsh north of the town grow the large pink moccasin 

 flower, Cypripediiim spectahile, and Hahenaria ffava, amidst deep mosses. 

 The Jionperus communis is found in this vicinity. On a steep northern 

 bank bordering the stream is a clump of Betula lenta, the cherry birch. 

 From this locality Dr. Pammel lists fifty-one shrubs and trees, among 

 them not already mentioned are Junipei^us Virgmiana, Betula lenta, and 

 Populus grayididentata. This last tree has taken possession near the 

 head of one ravine, and the trees have grown to a height of 50 to 60 feet. 

 North of the town the " Calamus pond " forms an excellent illustration 

 of the gradual filling of such standing waters by encroaching vegeta- 

 tion. Of the several acres once constituting the area of the pond, a large 

 part is now given over to reeds, cat-tails and arrow-leaf ; the calamus and 

 white water lily are both found in this neighborhood. Near one spring 

 is a beautiful growth of cress, introduced a few years ago. In the woods 

 the yellow bush-honeysuckle {Lonicera Sullwantii) is quite common. 

 As has been indicated, the exceptional plants of this region are northern 

 forms, and their occurrence is peculiar in its isolation. 



The region of the Altamont Moraine in countries further north has 

 hills and depressions characteristic of an ice-sculptured country. The 

 hills are rounded and steep ; the depressions frequently contain ponds 

 or bogs, often peat-filled. The black margins of these ponds were 

 dotted with the white bloom of two small species of arrow-leaf ; whilst 

 farther shoreward, reeds and rank grasses were growing. Occasionally 

 the tall Phragmites communis lined the roadways. The streams through- 

 out this part of the State are scantily wooded, the country being for the 

 most part open. 



It was the beginning of the season for Composites, and the sunflower 

 family was preparing a fine exhibition. We were just too early for the 

 blooming of asters and golden rod, which were vigorous and abundant. 



The second pine region visited was Allamakee County, seemingly 

 close upon the borders of the northern woods. This is in the driftless sec- 

 tion of Iowa. From our stopping place, Postville, in the southwestern 

 part of the county, a drive of nine miles brought us, by gradual descent, 



through two hundred feet of Trenton formation, to the valley of the 

 Yellow River. In its erosion to the present channel the river has left 

 exposed several groups of strata, thus affording variety in plants and 

 groups of plants, as we pass up and down the bluffs and along the 



