293 
country. The most nearly continuous and undisturbed areas of woodland 
are those which clothe the tops and sides of the bluffs which, as already 
mentioned, form .the outer margins of the river-bottoms. These are ex- 
clusively hardwood formations, the dominant tree at higher levels being 
the white oak (Quercus alba), with which are commonly associated the 
sugar maple (Acer saccharum), pig-nut hickory (Hichoria glabra), red 
oak (Guercus rubra), shell-bark hickory (Hicheria ovata), bass-wood 
(Tilia americana), elm (Ulinus sp. not det.), beech (Fagus ferruginea), 
dogwood (Cornus florida) and aspen (Populus tremuloides).  Where- 
ever these woodlands are sufficiently open to admit sunlight blue 
grass usually springs up and forms a continuous cover to the ground or, 
if the soil is exceptionally dry, an aggregation of more or less scattered 
tufts with interspaces of bare earth. Where the grass is thick one 
usually finds Welanoplus scudderi, while in places where it is short and 
scattered Spharagemon bolli and JMJelanoplus luridus are usually en- 
countered. Along the edges of the woods in undisturbed ground these more 
strictly sylvan types were observed to meet and to intermingle with a 
Campestral assemblage which usually included Syrbula admirabilis, Arphia 
ranthoplera, Chortophaga viridifasciata and Encoptolophus sordidus. In 
scrubby areas and in tall herbaceous growths -1tlanticus testaceus was 
fairly common. 
In strong contrast to the foregoing group is an assemblage character- 
istics of moist areas. Such areas most frequently occur at the outer 
margin of the river bottoms where the seepage from the neighboring bluffs 
keeps the ground perpetually moist and soggy. The soil in such places is 
a typical muck, frequently intermixed with gravel and silt. In nearly all 
the swamps I have visited the vegetable content of the soil appeared 
to be thoroughly decomposed. At one place (1) in a wet depression in 
the midst of a fairly large woods on the upland about one and a half 
miles northwest of West Lafayette the substratum was a true peat. In 
the bottomland swamps, however, the soil appears in all cases where I 
have examined it to be a muck. Such a swamp harbors a rich vegetation 
of which the dominant member in wetter spots is rice cutgrass (Homalo- 
cenchrus oryzoides) with which are often associated cat-tails (Vypha lati- 
folia) and jewel-weeds (/impatiens biflora). Surrounding the cutgrass 
areas in slightly dryer ground is usually a dense thicket composed of tall 
herbaceous plants, especially composites, among which I noted the taller 
ragweed (Ambrosia trifida), ironweed (Vernonia fasciculata), joepye- 
