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BOLETUS IGNARTUS. 
Agaric of the Oak. 
Class Cryptogamia. — Order FUNGI. 
Nat. Ord. Fungi, Linn, and Juss. 
Oen. Char. Fungus horizontal, porous beneath. 
This species of fungtis is a native of Britain, and is found growing 
on the trunks of trees, particularly on old decayed trunks of the oak 
and ash ; it varies in size from two to seven or eight inches in 
diameter. 
This fungus is generally sessile, but according to Withering it is 
sometimes found with a footstalk an inch in length, in form it some- 
what resembles a horse's hoof ; on the upper side it is smooth, scaly, 
and convex, but somewhat depressed in the centre, and marked with 
circular ridges of various colours ; the under side is flat, white or 
yellowish when young, but when old it becomes dark brown, ap- 
proaching to black, and full of minute pores ; the internal substance 
is fibrous, hard, tough, and of a tawny brownish colour ; the seeds 
are contained in the tubes. Balliard describes the tubes as being 
very slender, equal, and of the colour of tanned leather, in old 
plants stratified, a fresh layer being added every year. Pileus very 
hard, admitting of a pohsh by rubbing, marked with concentric 
bands or ridges, each broad ridge indicating a year's growth, and 
three or four small ones that of the different seasons of the year, 
varying extremely in colour. 
The Boletus which grows upon the oak is considered to be the 
best : for medicinal purposes it should be gathered in August or 
September, and kept perfectly dry. This species of Boletus appears 
to have derived its specific appellation, from its being used for 
tinder ; for this purpose, we are told, the Germans boil it in a strong 
ley, then dry it, and again boil it in a solution of saltpetre. In 
Franconia the inner substance of this fungus is prepared by beating 
it with a hammer, till it becomes soft, and resembles chaitnois 
leather ; it is then made use of for forming garments, and other 
purposes. 
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