OR. PLAIN TEACHING. 



239 



tatiun. The seeds of lichens are furnished 

 with a gummy and adhesive fluid, and being 

 scattered about by the winds, they fall upon 

 bare rocks and other surfaces, and to these 

 they attach themselves. Without soil, and 

 simply from moisture and the air, they vegetate, 

 and form a small central lichen ; others grow in 



circles around, till, in process of time, the 

 whole surface of the bare rock becomes covered 

 with a hoary coat. These lichens periodically 

 decay, and mouldering to the earth, form, with 

 the particles of the abraded rocks, a soil "which 

 is fitted for the reception of other plants, further 

 advanced in the scale of organization. 



14 



630. 



Both lichens and mosses possess 

 a commercial value. The former 

 are variously used in the arts as 

 pigments, and in some cases as 

 food. The quantity annually 

 imported into Great Britain for 

 dyeing purposes is estimated at 

 from £60.000 to £80,000 in 



value. The latter, in the form 

 of peat moss, is now used for 

 the manufacture of gas, and 

 some small towns in Ireland are 

 illuminated by it, the gas being 

 superior to that distilled from 

 coal. 



In walking through the woods 



we have discovered various forms 

 of fungi, popularly known as 

 mushrooms, toadstools, puff-balls, 



&c. But besides these large 

 examples of this very curious 

 order, there is a large number 



