140 



Mycologia 



study was of no value, or before the observations were com- 

 pleted for the series as a whole. In the Ohio area, where the 

 observations were made more frequently than was necessary for 

 most of the studies, the number of sets of data for each study 

 often does not reach the number of observations made. In the 

 Kentucky area, the number of sets of data recorded for each 

 study usually reaches the whole number for the area, except 

 when the study was destroyed in some manner. 



Where 2 or 3 studies lay side by side on a substratum, the 

 same number was used for the areas, followed by (a) or (b) to 

 indicate the second or the third of the series lying contiguously. 

 In the Ohio area, 2 sets of numbers were used, unfortunately, 1 

 for the studies of rate of growth and the other for the succession 

 studies. This accounts for the duplication of numbers for this 

 area. 



The areas are grouped below, not according to locality, but 

 according to character of the studies and after this according to 

 the plants involved, passing from lower to higher with respect to 

 somatic structure. 



Such expressions as 25 by 31 cm. across refer to a minimum 

 and a maximum distance across the plant and indicate nothing 

 regarding the form of the plants involved. 



Statements regarding shade caused by trees refer of course to 

 conditions while the leaves were on the deciduous trees. 



Lichen rhizoids are known to penetrate from 0.02 to 1.4 cm. 

 into rock ; but the algal-host cells have never been found deeper 

 than 0.5 mm. Though the rhizoids may have penetrated deeper 

 in some instances than the rocks were chipped in our areas tabu- 

 lated under primary successions, the algal hosts were certainly 

 removed in every instance. Consequently, any remnants of the 

 lichen rhizoids that may possibly have been left in the rocks in any 

 instance, through failure to chip deeply enough, probably died, 

 and the successions recorded as primary are all of this character 

 beyond reasonable doubt. 



Rate of Growth 

 Ohio, area 20, on the north side of a tulip tree 22 cm. in 

 diameter, in a low, shady wood. A well-fruited specimen of 



