258 MINNESOTA BOTANICAL STUDIES. 



This main ridge, capped bv Trenton limestone and underlaid 

 with St. Peter sandstone, represents in this region the farthest 

 eastward extension of the high rolling prairie of northeastern 

 Iowa. Typical prairie plants like Psoralen, argofhylla, Eryn- 

 gium yucccefoliiini, Mcsadenla tuberosa, Parthenmm integri- 

 folium and others find a home here, in fact prairie vegetation 

 in general is met with upon all the principal ridges. 



The sides of the bluffs and the upper narrowing valleys are 

 generally wooded, especially in the eastern portion where even 

 the ridges either have been or still remain forested. Southwest- 

 ward the timber disappears. 



Blackhammer township, adjoining Spring Grove on the north, 

 is considerably lower, and is cut through in the western portion 

 by Riceford creek, flowing north, and in the eastern portion by 

 Beaver creek, also north bound. 



The intervening region from north to south has an elevation 

 of about 1,100 feet and is essentially a rolling prairie. 



The bluffs along the two creeks are high and steep. As a 

 rule the slopes are heavily wooded except those facing south. 



The region of Fillmore county explored is traversed by the 

 South fork of Root river, and by Root river itself. The to- 

 pography and vegetation are essentially like that described for 

 southeastern Houston county in Mr. Wheeler's report. 



That part of Spring Grove township lying to the south of, 

 and westwardly merging into the high central ridge described, 

 proved the most interesting and best collecting ground of the 

 territory covered. 



It is interesting because of the fact that it borders immediately 

 upon a true prairie region and yet harbors such species as occur 

 typically in the northern part of the state. 



Among the most important of these should be mentioned : 



Botrychium obliquum, Sabbaldiopsis tridentata, 



Woodsia scopulina, Viola leconteana, 



Woodsia obtusa, Cornus canadensis, 



Jiiniperus sabina, Pyrola secunda, 



Carex albursina, Chimaphila umbellata, 



Lept orchis liliifolia, Arctostaphylos uva-ursi. 



It is worth noting that these, with the exception of Woodsia 

 scopulina, Woodsia obtusa, Junipcrus sabina and Carex albtir- 

 sina, were found in one place. 



