60 GUIDE TO THE STUDY OF LICHENS. 



collect poor, scrawny specimens, which will be cast 

 aside as better material is found. It will, of course, 

 not be necessary to urge the advice not to begin the 

 collection with the more insignificant crustose forms ; 

 the beginner will only too gladly leave these alone. 

 For some time attention should be devoted to the 

 larger foliose and fruticose lichens and to collect fer- 

 tile material in so far as that is possible. It must, 

 however, be remembered that some lichens rarely or 

 never bear apothecia. These may be collected and 

 retained until the fertile forms have been studied, 

 when little difficul ty will be found in classifying them, 

 at least generically. 



lichens occur in nearly all places where there is 

 ii not too much constant moisture and shade. They are 

 most numerous on the " weather-side " (northern ex- 

 posure) of trees, fences, old roofs and stone walls. 

 Travellers and hunters have time and again utilized 

 this knowledge to guide them in their journeys. Large 

 specimens of lichens occur on the bleakest rock ; fine 

 specimens of Cladonia occur on the soil in compara- 

 tively open ground ; some large foliose species (Pelti- 

 ffera) occur on the soil in shaded places. Bceornyces 

 J roseus, with its pink' apothecia, which is quite striking 

 in appearance although it is one of the crustose forms, 

 also occurs on the soil. 



From a study of the table of the continental range 

 of lichens one can obtain some idea as to what genera 

 may possibly be met with in a given locality. A col- 

 lector in the eastern, southern, or central states need 

 waste no time looking for Rocella tinctoria^ as this 



