113 



the fungal coat of the lichen inward, (to be seen only under a 

 high power microscope). This leathery coat is very thin, and in 

 some species is absent, when the podetium is described as de- 

 corticate, and may be covered by powdery granules, known as 

 soredia. When moist the green algal cells show through the 

 transparent fungal envelope, when present, and make the whole 

 plant much more conspicuous and handsome than when it is 

 dry, when the color is much duller. The decorticate forms are 

 whitish looking whether wet or dry. But all show up much more 

 plainly when moist, so that a rainy day is a good day to pursue 

 Cladonias. When the plants are badly weathered, by long cover- 

 ing under snow and ice in winter, or by a summer drought, 

 their appearance is much changed and they are more difficult 

 to identify, though if not too much affected by such experi- 

 ences, wetting will restore them to fullness and make their 

 characters clearer for study. 



The podetia, which give the most useful characters for 

 classification for the beginner, are densely branching, as in the 

 "Reindeer Mosses" and the Unciales (see key); short branched, 

 as in some of scarlet-fruited species; simple and unbranched in 

 others, and in some species bear cups ("Fairy Cups" of chil- 

 dren), which may be simple and sterile or may bear apothecia, 

 on the cup rims or on branches which in some cases may be 

 quite complicated, with or without squamules (scaly leaves), as 

 in forms of C. squamosa; or the cups may be in ranks of two to 

 five, growing out of the rims, as in C. gracilis; or out of the 

 middle of the cups, as in C. verticillata. 



Cladoniae reproduce in the three ways found in lichens, by 

 spores, by soredia, and by fragmentation. Reproduction by 

 spores produced in the apothecia, while most interesting, as 

 corresponding somewhat to the methods of mosses, hepatics and 

 ferns, is probably the least certain. The lichen spore, by reason 

 of the long habituation of the plants to symbiotic association 

 between certain fungal and algal species, must find, within a 

 brief time after dispersal, and within a small area about the 

 parent plant, free algal cells of the species with which the 

 lichen fungus concerned has established symbiosis. The chances 

 against such conjunctions must be very great, but the spores 

 are produced in large numbers and contact is evidently estab- 

 lished frequently enough to make the process sufficiently effec- 



