156 



Mycologia 



Summary 



One may speculate about possible or probable methods of 

 migration to the denuded quadrats ; but nothing is definitely 

 known further than seeing parts of Cladonia thalli lying on some 

 of the quadrats in early stages of ecesis. Other possible methods 

 are through fragmentation, through soredia, and through spores. 

 Some probable speculations regarding the means of ecesis might 

 have been made for some of the studies, but this would have 

 been scarcely worth while in the absence of definite data. 



Many of the results recorded above cannot be summarized 

 readily, and one must refer to the various studies for such data. 

 Of data which are readily summarizable, the more important are 

 given below. 



Graphis scripta increased in diameter from 0.2 to 0.75 cm. in 

 1 year. Vermcaria muralis increased in diameter 0.6 cm. in 1 

 year. Physic a pulverulenta increased in diameter for 7 years at 

 the rate of 0.42 cm. per year. Parmelia borreri increased in 

 diameter 1.3 cm. in 1 year. Parmelia caperdia increased in 

 diameter from 0.625 to 1.3 cm. per year for 8 years. Parmelia 

 conspersa increased in diameter for 7 years at the average rate 

 of 1. 16 cm. per year. Umbilicaria pustulata increased in diameter 

 for 8 years at the average rate of 0.36 cm. per year. Peltigera 

 canina grew 1.75 cm. in one direction in 1 year. 



Biatorella simplex replaced apothecia removed from sandstone 

 conglomerate in 4 years, and sterile Psora russellii growing on 

 limestone produced apothecia in the same time. An area of 

 Peltigera canina deprived of its apothecia produced 12 young 

 ones in 1 year. Smooth and sterile plants of Umbilicaria pustu- 

 lata growing on high sandstone became strongly pustulate and 

 produced apothecia in 7 years. Cladonia subsquamosa on sand- 

 stone conglomerate, when deprived of its podetia, regenerated 

 them or produced others in 4 years. The same plant removed 

 from the sandstone conglomerate, except minute fragments, pro- 

 duced squamules of normal size in 4 years and podetia of normal 

 size in 8 years. Cladonia pityrea on rails, deprived of its podetia 

 and squamules, except minute fragments, produced normal 

 squamules in 1 year and numerous podetia in 3 years. Cladonia 



