192 
Short on the Botany of Illinois. 
all relics of vegetable matter, both woody and herbaceous, is 
perhaps to be mainly ascribed the color of the soil, which for 
the most part is literally as black as coal, and in some situa¬ 
tions of two or three feet in depth. And to this excess of 
carbonaceous matter, imparted to the soil of these prairies, is 
it perhaps to be ascribed that their productions, both in culti¬ 
vated crops and natural growths, are by no means so rank or 
luxuriant as one might be led to expect. The Indian corn, 
though well-eared, was not so tall as I have frequently seen 
it in Kentucky and Ohio, on lands apparently much inferior 
in fertility; the different kinds of small grain, though heavily- 
headed, had a much shorter straw; and many of the natural 
productions, common to the Illinois prairies and the barrens 
of Kentucky, were less luxuriant in growth than I have ob¬ 
served them to be in the latter district, though the soil of the 
barrens has not the same appearance of fertility. This sub¬ 
ject deserves particular investigation, and an accurate analy¬ 
sis of the prairie soil might lead to very useful practical de¬ 
ductions. One of our fellow-travelers, a farmer by profes¬ 
sion, ascribed the appearance, above mentioned, to a ‘■sour¬ 
ness’ in the soil. But the amount of carbonaceous and alka¬ 
line matters resulting from such frequent burnings would 
rather lead to an opposite conclusion. 
Among the (Economical and medicinal plants of the prairies 
may be mentioned Gentiana ocliroleuca , the roots of which 
have somewhat the bitterness of the officinal species, (6r. 
lutea , of Europe,) Prenanthes serpentaria , several species of 
Liatris , the tuberous roots of which are possessed of acrid, 
pungent qualities, and Eryngium aquaticum ; all these plants 
have a considerable reputation, which perhaps is but little de¬ 
served, against the bites of poisonous serpents, and hence 
they are known indifferently by the names of ‘■snake-root,’ 
‘■button snake-root,’ rattle-snake’s masterpiece,’ &c. Fra- 
sera verticillata is not so frequently seen in the more open 
prairies as in the thinly-wooded barrens. Polygala Senega 
and Asclepias tuherosa are abundant in both these localities. 
The different species of Silphium mentioned, exude from their 
