Rate of Growth and Ecesis in Lichens 153 



siderable abundance on one of the rocks and more sparingly on 

 others. Other thalli were supposed to be the same, but were too 

 immature to be determined. Over most of the replaced portion 

 of the levee, the thalli could be seen only under the hand lens ; 

 but at a few points, the darker coloration of the rock could be 

 detected in passing. None of the plants bore apothecia. After 4 

 years a few of the thalli of Endocarpon pusillum showed 

 apothecia ; and hundreds of apothecia of Placodium aurellum 

 were scattered over some of the rocks. After 6 years the Endo- 

 carpon had developed many apothecia ; and one could easily detect 

 the coloration of the rocks, due to its thallus, from a standing 

 position 8 m. distant. The Placodium apothecia had not in- 

 creased greatly in number. Eight apothecia of Lecanora dispersa 

 were seen on one rock. After 8 years the coloration due to the 

 Endocarpon thallus could be seen easily over much of the rock 

 when standing 20 m. distant. The apothecia of the Placodium 

 were much more numerous, but would be noticed only under the 

 hand lens. The apothecia of the Lecanora were still rare and, 

 excepting one group which was easily visible from a standing posi- 

 tion, were readily visible only under a hand lens. The thalli of 

 the last 2 lichens could be seen only by aid of the lens. 



Ohio, area 12, a soil quadrat 1 m. square on high ground in an 

 open wood, denuded 5 cm. deep, removing all plant parts, except 

 roots of seed plants which extended deeper into the soil and 

 could not be pulled out. The quadrat, before being denuded, was 

 covered by lichens and mosses, with about 85 herbs and 2 seed- 

 ling trees scattered about within its limits. Cladonia furcata was 

 the only abundant lichen. Cladonia pyxidata was present in 

 several small patches, and a small cluster of Cladonia mitrula 

 was seen. After 1 year 36 clusters of Cladoniae were noted 

 within the quadrat, all so small as to be visible only on careful 

 observation and too rudimentary to be determined. Herbs, 

 mosses, and seedling trees were also appearing. After 5 years 

 the quadrat had reverted to the conditions found in the surround- 

 ing area so far as the lichens were concerned. Cladonia furcata 

 was again dominant and of the same size and appearance within 

 as without the quadrat. 



Kentucky, area 26, habitat like Kentucky, area 25, 11 a soil 



11 See Kentucky, area 25, p. 148. 



