ii6 FLOWERLESS PLANTS 



One point in connection with the growth 

 of hchens which is often noticed is the extreme 

 aversion of these plants to to\Mis. Hardy and 

 accommodating though they may be, pure air, 

 free from any taint of smoke, seems to be 

 essential to their welfare. This is rather sin- 

 gular when it is remembered how well man^^ 

 of our familiar plants have been able to adapt 

 themselves to town Ufe. It is possible that in 

 some way the air, laden with all kinds of impuri- 

 ties, prevents the httle algs from carrying out 

 their work, and thus the plants are unable to 

 flourish. \V"liatever is the reason, it is neces- 

 sary if we want Uchens to leave the streets 

 and houses far behind us, and we shall find 

 that the farther we go the more interesting 

 are the forms which we shall discover. 



One advantage which is attached to the 

 study of Uchens is that the matter can be 

 admirably taken up in the winter. Then, when 

 so much of the vegetation is resting, the lichens 

 are at their very best, thriving on the abund- 

 ance of moisture which is present during the 

 dull months of the j'ear. Considering there 

 are nearly two thousand well-established forms 

 in Great Britain, it is clear that any descrip- 



