THE RATE OF GROWTH AND ECESIS IN 

 LICHENS 1 



Bruce Fink 



One frequently sees statements concerning the rate of growth 

 in lichens ; but these are based, with few exceptions, on uncertain 

 observations rather than on measurements. Aside from results 

 obtained in cultures, the exceptions are a few measurements in 

 Lotsy, J. P., " Beitrage zur Biologie der Flechtenflora des Hain- 

 bergs bei Gottingen " (1890) and Howe, R. H., Jr., "Aspects of 

 New England lichens " (1908). In order to obtain sufficient data 

 for a safe conclusion regarding the rate of growth and ecesis in 

 lichens, the writer began a series of studies near Oxford, Ohio, 

 and another near Big Hill, Kentucky, during the summer of 1908. 

 At the request of a number of botanists, a preliminary statement 

 about the work near Oxford, Ohio, was given in " Licheno- 

 ecological studies from Beechwood Camp," published in The 

 Bryologist for March, 1909. During 8 years ending with the 

 summer of 1916, the lichens under observation had developed to 

 such an extent, for most of the studies, that nothing would be 

 gained by further observation. Therefore, the time has come 

 for a final report, which may be supplemented later by recording 

 further observations from a few of the areas. 



The studies near Oxford, Ohio, may be summarized thus: 17 

 for rate of growth, 18 for rate of primary succession, and 18 for 

 rate of secondary succession. Those near Big Hill, Kentucky, are 

 20 for rate of growth, 20 for primary succession, and 17 for 

 secondary succession. The succession studies also furnished 

 valuable data on the rate of growth. Of 107 studies begun, 45 

 are reported herein. For various reasons, the other 62 studies 

 gave no results worth recording. Some of them were destroyed 

 before valuable results could be obtained, while a few ran the 

 whole 8 years without giving data of sufficient value to warrant 

 publication. Some of the succession studies reverted to the con- 



1 Contributions from the Botanical Laboratory of Miami Univerity, — XIII. 



138 



