78 CLADONIACEAE— PARMELIACEAE 



Family 41. CLADONIACEAE 



Zahlbruckner 139 



Thallus of two kinds, one horizontal on the substratum, crustose, scaly to foli- 

 ose, the other consisting of erect clubshaped, cupshaped or filiform, simple or branched 

 podetia ; algae typically Pleurococcus ; apothecia terminal or lateral, mostly con- 

 vex to globose, with proper exciple only, except in Chlorocaulum ; spores colorless. 



I. Apothecia with proper exciple 



1. Podetia short, simple, rarely forked; apothecia terminal 



a. Podetia equal, not broadened above 

 (i) Podetia covering the surface 



(a) Hypothecium clear 



X. Spores i-celled Baeomyces 140 



y. Spores transeptate 



(x) Spores elliptic to rod-shaped 

 m. Spores 2-ceIled *Dibaeis 140 



n. Spores 4-celled 



(m) Algae bluegreen *Cyanobaeis 141 



(n) Algae yellow-green Heteromyces 141 



(y) Spores filiform, many-celled 



Gomphyllus 141 



(b) Hypothecium dark; spores i-celled 



Pilophorum 142 

 (2) Podetia marginal on a foliose thallus 



Gymnoderma 142 



b. Podetia broadened above into lobes or tongues bearing the hymenium on 



one side 

 (i) No algae below the hymenium; medulla uniform 



Glossodium 142 

 (2) Algae below the hymenium ; medulla with thicker strands 



Thysanothecium 142 



2. Podetia funnelform, cupshaped or more or less branched, large 



a. Spores i-celled ; podetia hollow Cladonia 143 



b. Spores 4-many-celled Stereocaulum 146 



c. Spores muriform Argopsis 146 



II. Apothecia with thalline exciple *Chlorocaulum 146 



Family 42. PARMELIACEAE 



Zahlbruckner 118, 124, 150, 195, 199, 207, 216 

 Thallus of one kind, podetia lacking, firm, not gelatinous, crustose, scaly, foli- 

 ose or fruticose, often with rhizoids, typically layered, algae typically yellow green, 

 but bluegreen in two subfamilies ; apothecia characterized by a thalline exciple, which 

 is rarely lacking, superficial, rarely immersed 



I. Thallus typically crustose, sometimes scaly or lobed at the margin 

 I. Algae Pleurococcus or Palmella, rarely Protococcus 

 a. Asci i-32-spored, mostly 8-spored 



(i) Disk conspicuous, not perithecioid Subfamily Leanorae 199 

 (a) Spores i-celled 



