178 GUIDE TO THE STUDY OP LICHENS. 



1. JEndocarpon hepaticum. Thallus of orbicular 

 scattered entire lobes, variable in size, closely ad- 

 nate to substratum (soil), margin turned upward, 

 pale flesh color, changing to dark-brown ; soralia some- 

 times present. Apothecia immersed. Spores typical, 

 13.5ya X V 



The color of the thallus is very likely due to 

 the presence of oxide of iron taken up from the 

 soil. 



2. Enndocarpon arhoreum. Thallus quite large, 

 somewhat lobate, margin usually turned downward, 

 attached by numerous long black rhizoids, upper 

 surface gray to light-brown ; lower surface dark. 

 Apothecia immersed, scattered. Spores typical, 13/x 

 X5/X. 



3. Endocarpon Jluviatile. Thallus quite large, 

 lobate at margin, only loosely attached to substra- 

 tum, upper surface gray to dark ; lower, gray to brown ; 

 few rhizoids. Apothecia not seen. 



Jf.. Endocarpon miniatwn. Thallus large, entire, 

 attached by an umbilicus, upper surface smooth, gray 

 to dark ; lower surface pustulate, dark to black, with 

 numerous fine rhizoids. Apothecia immersed and uni- 

 formly scattered, appearing as minute dark specks. 

 Spores typical, 13.5/x X 5/x. 



The pustules on the lower surface prove on exami- 

 nation to be apothecia, bearing spores. A so-called 

 variety consists of numerous imbricate ascending lobes 

 instead of a single thallus. 



A coloring substance is extracted from this lichen, 

 which is, however, said to be of an inferior quality. 



