162 



Cincinnati Society of Natural Hisiory. 



II. RETICULARIACE^. Wall of the sporangium a 

 thin membrane, with distinct fibrous thickenings; the mem- 

 brane, or at least certain portions of it, disappearing at 

 maturity. 



a. Sporangia combijied into an cethalium. 



4. Reticularia. The persistent fibrous thickenings of 

 the sporangial walls irregular and without any vesicles. 



5. Brefeldia. The persistent fibrous thickenings of the 

 sporangial walls, bearing polycellular vesicles. 



6. Clathroptychium. The persistent fibrous thicken- 

 ings consisting of six simple threads extending from the 

 angles of the hexagonal apex downward to the base of the 

 sporangium. 



b. Sporangia simple and stipiiate. 



7. Cribraria. Capillitium of slender threads combined 

 into a net-work of polygonal meshes. 



8. Dictydium. Capillitium of numerous convergent ribs 

 which extend from base to apex and are united by fine trans- 

 verse fibers, thus forming a net-work of rectangular meshes. 



III. LYCOGA.LACEAE. Aethalium with a firm mem- 

 branaceous wall, from the inner surface of which proceed 

 numerous slender warted tubules (?). 



9. Lycogaea. Aethalia subglobose. 



§2. CAEONEMATA. 



Sporangia containing no lime and without a columella ; ca- 

 pillitium of bright -colored much elongated threads, which 

 traverse the interior of the sporangium and are intermingled 

 with the spores, usually kinked and coiled, and by reason 

 of this exhibiting elasticity ; the walls of the threads marked 

 externally by characteristic thickenings. 



IV. PERICHAENACEAE. Sporangia sessile; tubules 

 of the capillitium proceeding from numerous points of the 



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