39 



branched, seldom rounded-difform, mostly innate ; the exciple col- 

 ored or black, and more often colorless below, almost always bor- 

 dered by an accessory thalline or thalloid one. Spores 4-plnriloc., 

 or murlform, brown or decolorate. Th. uniform or almost obsolete. 

 A large and difficult, mostly southern genus. Several of our spp. 

 are undescribed, and new ones may be expected to occur. Only 3 

 or 4 spp. occur in our temperate region. 



Fam. 3. Glyphidei. Many apoth. collected in a common, 

 cushion-like, thalloid receptacle (stroma.) 



Genus 57. Chiodeoton Ach. Apoth. rounded-difform or ob- 

 long, plano-convex, immarginate, immersed in a white stroma. 

 Spores 4-pluriloc., or rarely muriform, almost always uncolored. 

 Th. uniform. A small tropical genus. — Thelotrema Calif ornicum 

 Tuck., Obs. 1877, p. 177, is a Chiodecton. 



Genus 68. Gltphis Ach., Mont., Nyl. Apoth. rounded or ob- 

 long, concave, in a white stroma. Spores 4-pluriloc., brown or de- 

 colorate. Th. uniform. A small, tropical genus, of which we have 

 one collective sp. 



Fam. 4. Arthoniei. Apoth. difiform, without proper margin, 

 commonly confluent, and now evidently compound. 



Genus .57. Abthonia Ach., Nyl. Apoth. rounded or oblong, 

 now with an accessory thalloid margin, the proper margin deficient, 

 more or less aggregated, or confluent in an irregular pseudo-stroma. 

 (Paraphyses mostly obsolete.) Spores, in pyriform or globose, 

 rarely clavate thekes, oblong-ovoid, or oblong, or very rarely fusi- 

 form, 2-4-pluriloc., or muriform, brown or decolorate. Thallus 

 uniform, or scanty and subcortical. A large and diflBicult genus, of 

 which we have many new spp., and others doubtless are to be dis- 

 covered. 



Genus 58. A&trium Fr. Apoth. rounded or oblong, waxy, im- 

 marginate. Spores in clavate thekes, simple, hardly colored. 

 Thallus scarcely visible. A very small genus, of which we have 1 

 sp. of the Atlantic coast. 



Genus 59. Mycopokum (F1.) Nyl. Apoth. rounded or oblong, 

 black, finally compound ; a difform pseudo-stroma including 1 to 6 

 hymenia. Spores 2-4 loc, or muriform, brown or decolorate. Th. 

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

 six or seven spp., mostly undetermined. It includes Melanotheca 

 of authors, and some of the spp. are referred by Minks to his genus 



