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Genus 49. Lecidea (Ach., Fr.) Apoth. patellseform, or now 

 cephaloid, (very rarely lecanoroid.) Spores simple, becoming fusi- 

 forpi and acicular and 2-4-pluriloG., colorless. Tli. now lobulate or 

 caulescent, mostly uniform. The forms with lobulate Th. consti- 

 tute the § Thalloedema ; those with simple spores § Eulecidea ; with 

 2-4-plurilocular spores § Toninia ; with numerous spores § Sporas- 

 tatia. A very large and diffleult genus, with a complicated syilono- 

 my. Many of our spp. are undetermined. 



Genus 50. Buellia (DN.) Tuck. Differs from Lecidea in hav- 

 ing brown spores, either 2-4 loc, or muriform. The forms with 

 lobulate Th. are § Catolechia ; with 2-4 loc. spores § Eubuellia ; with 

 muriform spores § Rhizocarpon. A large genus. 



Tribe III. GRAPHIDACEI. Apoth. difform, oftener elon- 

 gated, (lirellseform,) margined normally only by the proper exciple, 

 which is now indistinct. 



Fam. 1. Lecanactidei. Apoth. more or less rounded, or less 

 commonly elongated, margined. 



Genus 51. Leoanactis (Eschw., Kbr.) Tuck. Apoth. rounded, 

 or more rarely oblong, black. Spores from dactyloid at length fu- 

 siform-oblong, 4-plurilocular, colorless. Th. uniform. A small 

 genus. 



Genus 52. Platygrapha Nyl. Apoth. rounded or oblong ; the 

 proper exciple more or less obscure, bordered by an accessory thai- 

 line or thalloid one. Spores 4-plurilocular, colorless. Th. uniform. 

 A small genus, mostly of southern regions. One sp. occurs in N. E. 



Genus 53. Melaspilea Nyl. Apoth. rounded or oblong, black. 

 Spores 2 loc, brown, or decolorate. Th. uniform. A small genus. 



Fam. 2. Opegraphei. Apoth. normally lirellseform. 



Genus 54. Opegkapha (Humb.) Ach , Nyl. Apoth. lirellse- 

 form, rarely rounded-difform, oftener simple, mostly superficial, the 

 exciple almost always black throughout. Spores dactyloid or fusi- 

 form, 2-4-plnriloc., brown, or oftener decolorate. Th. uniform. A 

 genus of numerous spp. 



Genus 55. Xtlogkapha Fr., Nyl. Apoth. now angulate-patel- 

 Iseform, oftener lirellseform ; the exciple softish, originally pale, at 

 length black. Spores simple, colorless, (in a foreign sp. muriform.) 

 Th. uniform, or almost obsolete. A small genus, of which we have 

 4 spp., two of which are undescribed. 



Genus 56. Geaphis Ach., Nyl. Apoth. lirellaeform, mostly 



