5P 



THE PLANT WORLD 



An example started no doubt as favorably on the rough 

 and grooved gray bark of the White Ash {Frax'mus ameri- 

 cona Linn) for example, develops into a broken disintegrated 

 specimen lacking symmetry, and its true character of growth 

 is nearly obliterated by the uneveness of the substratum. 



FIGURE 3.— Typical plant, showing a younger one growing 

 over the center of the first. Maple (Acer) substratum. 



(See Fig. 4.) Again on a vegetable substratum this lichen 

 never grows in company with Pannelia conspersa (Ehrh.) 

 Ach., a species with which it is often superficially confused. 

 Whereas when it grows on a rock it is often accompanied by 

 the above named species, and the separation is at once made 

 difficult. Then still again Pannelia caperata rarely fruits, 



