14 Charles E. Besscy 



nidia) ; apothecia mostly convex, terminal or lateral on vertical 

 stalks (podetia). Beomyces, Cladonia, Stereocaulon. (Pf. I, 

 I*, 139.) 



Family 13. Gyrophoraceae. Foliose, coriaceous lichens at- 

 tached at a single point, with Pleurococcus gonidia ; apothecia flat, 

 sessile or stalked, margined. Gyrophora, Umbilicaria. (Pf. I, 

 I*, 147.) 



Family 14. Acarosporaceae. Crustaceoiis, scaly to foliose 

 lichens with Pleurococcus or Protococcus gonidia; the thallus 

 poorly developed in most cases; apothecia in thalline warts in 

 which they are sunken. Thelocarpon, Acarospora, Biatorella. 

 (Pf. I, I*,' 150.) 



Family 15. Ephebaceae. Dwarf-fruticose or filiform-branched, 

 crustaceous to scaly lichens with Scytonema or Stigonema go- 

 nidia ; apothecia small, sunken or superficial. Spilonema, Ephebe. 

 (Pf. I, I*, 154.) 



Family 16. Pyrenopsidaceae. Crustaceous, foliose to fruticose 

 lichens, with Glococapsa^ Chroococcus, or Xanthocapsa gonidia; 

 apothecia small, closed at first. Pyrenopsis, Synalissa, Thyrea. 

 (Pf. I, I*, 158.) 



Family 17. Lichinaceae. Crustaceous to scaly or fruticose- 

 branched lichens, with Rivularia gonidia ; apothecia spheroidal, 

 closed, sunken, with a bright-colored margin. Pterygium, Lichina. 

 (Pf. I, I*, 164.) 



Family 18. Collemataceae. Gelatinous to crustaceous, scaly, 

 foliose or fruticose lichens, with Nostoc gonidia ; apothecia closed 

 or open, sunken or sessile, not margined. Physma, Collema, Lep- 

 togium. (Pf. I, i*, 168.) 



Family 19. Heppiaceae. Scaly, foliose, irregular or fruticose 

 lichens with Scytonema gonidia; apothecia sunken, not margined. 

 Heppia. (Pf. I, i*, 176.) 



Family 20. Pannariaceae. Crustaceous-corneous, to scaly and 

 foliose lichens (not gelatinous),' with Nostoc or Scytonema go- 



50 



