366 MINNESOTA BOTANICAL STUDIES. 
Dirca palustris, 
Pellea stellerz, 
Viburnum opulus. 
Acer spicatum, 
Adoxa moschatellina, 
- Betula lutea, 
Circea alpina, 
VEGETATION OF WOODED SLOPES AND RAVINES. 
This group of plants borders and perhaps encroaches upon 
the moist woods of the valley upon the one hand and the ridge 
forest upon the other. It covers a large area but does not repre- 
sent the variety of species that are found in the moist woods of 
the valley. 
Some of the plants of the wooded slopes and ravines are 
Asplenium acrostichozdes, 
Ashplenium filix-femina, 
Castilleja coccinea, 
Cypripedium hirsutum, 
Cypripedium spectabilis, 
Cystopteris fragilis, 
Epilobium coloratun, 
Erechtites hieractfolia, 
Eupatorium ageratotdes, 
Falcata comosa, 
Flieracium umbellatum, 
Flieracium scabrum., 
flypericum maculata, 
flypericum majus, 
Lilium umbellatum, 
Lobelia cordifolia, 
Lobeha inflata, 
Onoclea struthiopterts, 
Osmunda claytoniana, 
Panax quinguefolia, 
Pedicularis canadensis, 
Pol ‘ygonatum commutatum, 
Pteris aguilina, 
Rubus occidentalis, 
Fubus villosus, 
Szlene stellata, 
Smilax herbacea, 
Smilax hispida. 
RIDGE FOREST VEGETATION. 
Most of the woods upon the ridges are rather open and there- 
fore present somewhat xerophytic conditions. The principal 
forest trees of the ridges are those which have been previously 
mentioned, 2. e., Betula papyrifera, Hicoria ovata, Quercus 
alba and Quercus macrocarpa. Scattered trees of other kinds 
are found on special areas. On the point of a bluff near the 
village of Freeburg, several trees of Gymnocladus diotcus were 
found in one of the most exposed locations that it could obtain. 
This is a very unusual location for this tree. Prunus virginiana, 
Juniperus virginiana, Tilia americana and Celtis occidentales 
quite frequently grow near or on the rocky summits of the bluffs 
but do not cover large areas. 
