Feb., 1913.] Characteristic Plants of a Typical Prairie. 
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tion on the young flood-plains of a forested region like Ohio. They 
owe their existence to the presence of the river and not to the 
climatic conditions. 
The prairie fire, although not the cause of the prairies, had, 
nevertheless, a profound effect on their vegetation. When the 
fires swept over the prairie in the spring, it burned up everything 
down to the ground, and perennial herbs and shrubs had each 
year to meet anew the competition above ground of the all-con¬ 
quering grasses. Frequently the fires occurred in the fall and 
thus the soil was exposed, without covering, during the entire 
winter to dryness, wind and cold. Since the fires have ceased 
even the patches of prairie still remaining are undergoing a rapid 
and remarkable change in vegetation. The change in the relative 
abundance of certain species is no less interesting than the arrival 
of new forms from other regions. 
After the characteristic grasses, the most prominent members 
of the prairie vegetation are a number of shrubs and perennial 
geophilous herbs. The latter are usually crownformers, often 
with exceedingly long taproots. When one sees such plants 
exposed in the banks of a stream or an arroyo, one realizes what a 
large part of the vegetation is underground in summer as well 
as in winter. 
The woody or semi-woody species are few in number, though 
several are among the characteristic prairie plants. The most 
important one in the region under consideration is the shoe-string, 
Amorpha canescens Pursh, which is a low shrub a foot or two in 
height. Others are, Rosa arkansana Port., Arkansas Rose, 
Meriolix serrulata (Nutt.) Walp., Tooth-leaf Evening-primrose, 
and Morongia uncinata (Willd.) Britt., Sensitive-brier. The 
latter is only slightly woody. In the ravines, Amorpha fruticosa 
L., false indigo, is especially abundant on the banks of ponds. 
Salix fluviatilis Nutt., Sandbar willow, grows in small dense 
thickets in moist ravines and is occasionally present on banks and 
hillsides. In such situations, however, the shrub is always 
very small. 
Very few seedless plants thrive on a typical prairie. There are 
no ferns on the prairie proper but Wocdsia obtusa (Spreng.) Torr. 
grows on moist sandstone cliffs along with several species of mosses, 
liverworts, and lichens. Equisetum kansanum Schaff. occurs on 
clayey banks and slopes and Marsilea vestita H. & G. grows 
occasionally in buffalo-wallows in low places. The Marsilea 
seems to be near its eastern limit and is properly a plant of the 
plains. There are very few mosses but some small ground-loving 
lichens occur especially on the hills and Nostoc commune Vauch. 
is abundant on the banks of ravines. The giant puffball, Lyco- 
perdon giganteum Batsch., often occurs in large numbers and in 
suitable seasons various other species of puffballs, toadstools and 
stink-horns make their appearance. 
