

7. GRAPHIDACEAE 



Thallus crustose, superficial or entirely within the substratum, little or 

 no differentiation into layers. Apothecia lirellae form, black, elongated to 

 circular, single or clustered, not in a stroma ; proper margin usually well 

 developed, thalline margin present or absent ; asci 4-8-spored ; spores hya- 

 line, or brown, nonseptate to multiseptate. 



Alga Palmella or Trent epohlia. 



A. Spores simple; thallus entirely within the substratum 9. Xylographa 



A. Spores septate ; thallus usually evident on the surface of the substratum. 

 B. Paraphyses branched and interwoven; apothecia immersed and then 



erumpent 11. Graphis 



B. Paraphyses unbranched and distinct ; apothecia superficial. 



10. Opegrapha 



9. Xylographa Fries, Fl. Scan. 344. 1835. 



Thallus crustose or entirely within the substratum. Apothecia black or 

 brown, erumpent, circular to linear, clustered or in parallel rows; proper 

 margin thin and dark colored, thalline margin absent ; hypothecium hyaline 

 to slightly colored ; paraphyses several-celled, rarely branched ; asci 8- 

 spored ; spores hyaline, nonseptate. 



Alga Palmella. 



A. Apothecia in more or less parallel lines, elongated, reaching 3.0 mm. in 

 length 1. Z. abietina 



A. Apothecia irregularly clustered, circular to oblong not exceeding 0.6 

 mm. in length 2. X. hians 



1. Xylographa abietina (Pers.) Zahlbr. Cat. Lich. Univ. 2:151. 1924. 

 Hysterium abietinum Pers. Obser. Mycol. 1 :1796. Xylographa paraUela 

 (Ach.) Behlen & Desberg. 



Thallus usually entirely within the substratum, rarely showing on the 

 surface as a grayish coloration. Apothecia 0.5-3.0 x 0.2-0.5 mm. long, and 

 narrow, innate, finally erumpent, more or less in parallel lines ; disk black, 

 varying from closed to open, concave to flat ; proper margin black ; spores 

 hyaline, ellipsoid, nonseptate, 11.0-16.5 x 5.0-6.6 fx. 



(19) 



