148 



Mycologia 



had taken the other one-fourth. The quadrat had reverted to 

 conditions found over the remainder of the rock ; for Leptogium 

 lacerum had largely disappeared, while V errucaria nigrescens 

 had become conspicuous without the quadrat as well as within 

 it. The Physcia was sterile both within and without the quadrat. 



Kentucky, area 12, on the upper surface of a boulder 80 by 

 140 cm. and 30 cm. high, lying on a dry hillside, the upper surface 

 making an angle of 35 degrees with the horizon and exposed to 

 the sun, except during half of the forenoon. A small area of 

 Psora russellii was stripped of apothecia. After 10 months the 

 area showed 2 small apothecia. After 4 years 50 apothecia were 

 found, some of them of average size for the species. After 8 

 years more than 100 apothecia were present. 



Kentucky, area 14, a quadrat 30 by 40 cm. on a limestone rock 

 40 by 100 cm. and 75 cm. high, lying in an open, dry wood where 

 poorly shaded, the upper surface making an angle of 15 degrees 

 with the horizon. Leptogium lacerum and the moss on which 

 it was growing were rubbed and scraped from the rock, except 

 bits of the moss and particles of the lichen which adhered to the 

 rock, especially in depressions of the rock surface. After 4 years 

 the moss was found returning over 300 or more small areas, many 

 of them bearing specimens of Leptogium lacerum 2 to 10 mm. 

 across. Very little change occurred during the next 4 years. 



Kentucky, area 25, a quadrat 32.5 by 45 cm. at the top of a 

 high, dry cliff facing northward, the quadrat on bare rock at the 

 edge of the cliff, but on soil 16 cm. deep at the opposite side, 

 partially shaded during the forenoon by low shrubs. Many plants 

 of Cladonia uncialis, C. cristatella, C. fimbriata, and C. pyxidata 

 were torn and pounded from the Polytrichum on which they were 

 growing, and the fragments were strewn over the quadrat. After 

 4 years Cladonia uncialis and C. pyxidata were both abundant 

 and well developed with many podetia of normal form and size. 

 After 8 years the 2 lichens had taken the quadrat, and about one- 

 fourth of the podetia of Cladonia pyxidata bore apothecia. 



Kentucky, area 24, habitat similar to Kentucky 25, 7 but back 

 2 m. from the edge of the cliff, on soil 0.5 m. deep over the rock. 

 The quadrat, 10 by 14 cm., was covered by Cladonia uncialis 



7 See the area discussed next above. 



