FUNGI, OR 3IUSROOMS. 
249 
Fig. 51. 
appearance ; here the saucer-like bodies in which the seeds are 
imbedded are very apparent. (6) is a lichen resembling a drink- 
ing glass, (c) is the rein-deer moss, furnishing almost the sole 
food of that useful animal so important to the existence of the 
Laplander. In the middle of Europe it grows only to the 
height of two or three inches ; but in Lapland it sometimes at- 
tains to the height of one foot and a half. 
Many of the lichens are useful on account of their colouring 
matter. Litmus , which is so common as a chemical test for 
acid sand alkalies, is obtained from a species of white lichen, called 
Orchal, or Archil which is also used for giving a crimson color to 
wool and silk : and the powder called cudbear used for dying 
purple, is obtained from lichen. The order Lichen has some- 
times been included under one genus called lichen, and placed 
the order Algce. 
Fungi, or mushrooms. 
The 6 tk order contains the Mushrooms ; these never exhibit 
any appearance of green herbage, they are generally corky, 
fleshy, or mould-like, varying much in form and colour. The 
fruit of some is external, of others internal. They are often of 
very quick growth aud short duration, hence the expression which 
is often ironically made, a “ character of mushroom growth,” 
when a person has suddenly acquired consequence. The genus 
Agaricus, which contains the common eatable mushroom, has 
a convex, scaly, white head, called a pileus ; this is supported 
on a stalk called a stipe. On the under surface of the pileus or 
cup, are seen many flesh-coloured membranes called gills. 
These gills in the young state of the mushroom, are concealed 
by a wrapper called a volva, which is considered as a kind of 
calyx. As the mushroom becomes older, the volva bursts and 
Litmus a chemical te3t for acids — Order Mushrooms. 
