FUNGI. 221 



waxy plate or layer, in which are imbedded sporules in- 

 closed in little membranous thecce. (Hooker) . 



Geographical Relations. To be found from the equa- 

 tor to the poles ; but are plants rather of the northern 

 than southern regions. 



Properties. Mucilaginous and nutritive from their 

 amylaceous matter ; but sometimes bitter. They afford 

 likewise good dyes. 



Officinal Plant. 

 Cetraria islandica. 



61. FUNGI. 



Aerial plants composed chiefly of cellular tissue, but 

 which sometimes has fibrous tissue intermixed with it. 

 Thallus varying in texture, being soft, leathery, or waxy, 

 etc. ; and often coloured in the most showy and brilliant 

 manner, though seldom green, which colour, when it does 

 occur, is of a lurid metallic tint ; but sometimes wanting. 

 Spores or reproductive germs always present ; but some- 

 times unconnected by any common receptacle or thallus ; 

 in a few cases quite naked, but mostly covered or en- 

 closed by an hymenium, perithecium, or peridium. 



Plants found upon decaying animal or vegetable mat- 

 ter in abundance, and upon living vegetables, and grow- 

 ing upon or quite beneath the surface of the earth, vary- 

 ing in size from a minute cellule to a mass of two or 

 three feet in diameter. 



Geographical Relations. Chiefly affecting northern 

 latitudes and the northern parts of the temperate zone 

 u 3 



