GRAPHIDACEAE 



105 



A. Apothecia separate, single or cespitose 



1. Thallus lacking, parasitic on lichens or on bark 



a. Parasitic5><n lichens 



(1) Spores 1-celled 



(2) Spores 2-celled 



(3) Spores x-celled 



b. Parasitic on bark 



(1) Spores 2-celled 



(2) Spores x-celled 



(3) Spores muriform 



2. Thallus present, crustose or uniform 



a. Apothecia without an exciple, i.e., not mar- 

 gined 



(1) Algae Palmclla or Protococcus; spores 



hyaline 



(a) Spores 2-celled 



(b) Spores x-celled 



(c) Spores muriform 



(2) Algae Trentepohlia 



(a) Spores 2-x-celled 

 X. Spores hyaline 



(x) Spores 2-celled 

 (y) Spores x-celled 

 y. Spores brownish to brown, x-celled 

 (x) Perithecia cespitose; spores brownish 

 (y) Perithecia not cespitose; spores 

 brown 



(b) Spores muriform 



(3) Algae Phyllactidium; spores hyaline 



(a) Spores 2-celled 



(b) Spores x-celled 



(c) Spores muriform 



b. Apothecia margined with a distinct proper 

 exciple as a rule 

 (1) Thallus without cortex 

 (a) Algae Palmella 

 X. Apothecia with a single hymenium 

 (x) Spores hyaline or subhyaline 

 m. Spores 1-celled 

 (m) Hypothecium clear or brownish 

 (n) Hypothecium black, carbonous 

 n. Spores x-celled 

 (y) Spores dark 

 m. Spores x-celled 

 n. Spores finally muriform 

 y. Apothecia with 2-4 parallel hymenia; 

 spores hyaline 

 (x) Spores 1-celled 

 (y) Spores x-celled 

 (b) Algae Trentepohlia 

 X. Asci 1-8 spored 

 (x) Spores hyaline 

 m. Spores transeptate 



(m) Paraphyses simple, not united 



Subfamily Arthoniae 



Phacopsis R 419 

 Conida R 420 

 Celidium R 425 



Lecideopsis R 432 

 Arthonia R 435; 23 

 Arthothelium R 438 



Subfamily Arthoniae 



Allarthonia 106 

 Plearthonis 106 

 AUarthothelium 107 



Coniocarpum 106 

 Arthonia 104 



Synarthonia 107 



Gymnographa 110 

 Arthothelium 106 



Merarthonis 107 

 Arthoniopsis 107 

 Trichophyma 107 



Subfamily Graphidae 



Xylographa 108 

 Lithographa 108 

 Aulaxina 109 



Encephalographa 109 

 Xyloschistes 110 



Ptychographa 109 

 Diplogramma 109 



