Rate of Growth and Ecesis in Lichens 143 



After 2 years it was 2 cm. across in one direction and 2.4 cm. 

 across at right angles. After 3 years the plant was 2.6 and 2.9 

 cm. across in the 2 directions respectively. 



Ohio, area 7, habitat similar to Ohio, area 5, 4 but only 0.2 m. 

 from the ground on the north side of the tree by a little east. 

 The specimen of Parmelia consp'ersa studied was smooth and 

 sterile and 1 by 1.6 cm. across. After 1 year the plant was 1.3 

 by 1.9 cm. across. After 2 years it was 2.1 by 3 cm.; after 3 

 years, 3.5 by 4.1 cm. ; after 5 years, 4.5 by 5 cm. ; after 7 years, 

 7 by 8 cm.; and after 8 years, 10.2 by 12.9 cm. across. After 

 7 years the central portion of the thallus, about 2 cm. across, bore 

 scattered isidioid branchlets, which increased in number and 

 area covered during the following year. 



Ohio, area 3, on next to the top rail of a fence, well shaded by 

 a mesophytic wood, except late in the afternoon. A smooth and 

 sterile specimen of Parmelia caperata 1.2 cm. across was marked. 

 After 1 year the plant was 1.75 cm. across. After 2 years, 3 by 

 3.5 cm. ; after 3 years, 5 cm. ; after 4 years, 5.7 by 6.5 cm. ; after 

 6 years, 7.3 by 9 cm. ; and after 8 years, 10 by 13 cm. across. At 

 the conclusion of the observations the central portion of the 

 thallus half way to the margins was thickly covered with isidioid 

 branchlets. 



Ohio, area 1, on the northwest side of a rail lying on the ground, 

 along the north border of a high, dry wood, well shaded except 

 late in the afternoon. A quadrat of Cladonia pityrea 10 by 16 

 cm., was marked. No podetia were present in the quadrat, and 

 the horizontal thallus consisted of small or minute, scattered 

 squamules, many of them too small to be seen with the eye. 

 After 2 years the quadrat was thickly covered with squamules of 

 normal size for the species, and many podetia had appeared. A 

 large proportion of these were detected under the hand lens, but 

 19 were visible to the eye and varied from 2 to 4 mm. long 



Ohio, area 22, on a hornblende boulder 2.5 by 4 cm., and 2 cm. 

 high, the upper surface facing westward at an angle of 30 degrees 

 with the hroizon and well shaded, except for an hour shortly 

 before mid-afternoon. A specimen of Physica pulvernlenta and 

 one of Parmelia conspersa were marked. The plants were 2.4 by 



4 See Ohio, area 5, p. 141. 



