Tribe VI. CLADONIEI Nyl. Thallus foliaceous or fruticulose, 

 with fistulose podetia : apothecia terminal on the podetia, rarely 

 sessile on the basal thallus, biatorine. 



31. Pycnothelia Duf. Thallus granuloso-crustaceous, podetia 

 clavate, papillasform, glabrous : apothecia brown, with simple spores; 

 spermogones with simplish sterigmata and curved spermatia. 



32. Cladonia Hill. Thallus foliolose or squamulose; podetia 

 branched or scyphose, pulverulent and squamose : apothecia brown 

 or scarlet, with simple spores ; spermogones with simplish sterig- 

 mata and cylindrical straight or somewhat curved spermatia. 



33. Cladina Nyl. Thallus leafless ; podetia ascyphous, branched, 

 smoothish : apothecia brown, with simple spores ; spermogones with 

 simplish sterigmata and straight or usually curved spermatia. 



Series III. RAMALODEI Nyl. ThaUus efoliolose, fruticulose 

 or filamentose : apothecia generally lecanorine or parmelioid. 



Tribe VII. ROCCELLEI Nyl. Thallus simpHsh or branched, 

 internally with filamentose medulla : apothecia often irregular, 

 adnate, terminal or lateral. 



34! Roccella DC. Thallus fruticulose from a common base: 

 apothecia normally lecanorine, blackish, with 3-septate spores ; 

 spermogones with simplish sterigmata and arcuate epermatia. 



Tribe VIII. SIPHTJLEI Nyl. Thallus podetiiform, simple or 

 fruticulose, internally with filamentose or fistulose medulla : apo- 

 thecia not rightly known. 



35. Thamnolia Ach. Thallus subulato-stipitate, internally fistu- 

 lose : apothecia unknown ; spermogones with jointed sterigmata and 

 cylindrical, slightly apically incrassate spermatia. 



Tribe IX. RAMALINEI Nyl. Thallus fruticuloso-foliaceous, 

 rounded or compressed, with woolly medulla : apothecia lecanorine, 

 scutellate. 



36. Ramalina Ach. Thallus ramoso-laciniate, medulla arach- 

 noid: apothecia terminal or lateral, subconcolorous, with 1-septate 

 spores ; spermogones with pauci-articulate sterigmata and straight 

 cylindrical or oblongo-cylindrical spermatia. 



Tribe X. USNEEI Nyl. ThaUus very much branched, rounded 

 or compressed, with firm medullary axis : apothecia parmelioid, 

 peltate. 



