28. Laurera] 6. ASTROTHELIACEAE 63 



9. Trypethelium eluteriae Spreng., Einl. Stud. Krypt. Gewach. 351. 1804. 



Trypethelium Sprengelii Ach. 



Thallus very thin, rudimentary, smooth to rough, yellowish gray to brownish, 

 the superficial portion sometimes absent, and the imbedded portion indicated at 

 the surface as a yellowish gray coloration; perithecia minute, 0.05-0.2 mm. across, 

 heaped together in strongly convex, somewhat irregular, brownish to brown stro- 

 mata, or rarely solitary in stromatic elevations, the ostiole minute, black; spores 

 fusiform, 9-13-septate, 40-54 X 10-13 /*. 



On trees, Florida. 



OTHER SPECIES REPORTED 



Trypethelium favulosum Ach. — Florida. 

 Trypethelium porosum Ach. — Maryland. 

 Trypethelium variatum Nyl. — Florida. 



28. Laurera Reich., Der Deutsch. Bot. 15. 1841. 



Thallus crustose, rudimentary, partly or wholly within the substratum, the 

 superficial portion thin, smooth to rough, devoid of differentiation into layers; 

 stroma round to irregular, hemispherical to flat or more or less indistinct; perithecia 

 minute to small or middle-sized, 1-several immersed in each stroma, the wall com- 

 plete, the superficial portion convex, flat or depressed, the ostiole scarcely visible; 

 hypothecium hyaline to brown; hymenium hyaline; paraphyses branched and net- 

 like interwoven; asci cylindrico-clavate ; spores 2-8, hyaline, oblong to oblong- 

 ellipsoid or ellipsoid, transversely and longitudinally septate, the cells cubical or 

 cylindrical. 



The algal host is Trentepohlia. 



A. Spores more than 100 fi in length 2. L. megasperma 



A. Spores rarely more than 50 /j, in length 1, L. madreporiformis 



1. Laurera madreporiformis (Eschw.) Riddle; Howe, Torreya 16:50. 1916. 



Trypethelium madreporiforme Eschw., Syst. Lich. 26. f . 24 a-c. 1824. 



Thallus very thin, smooth, greenish gray to brownish; perithecia minute to 

 small, 0.2-0.5 mm. across, several immersed in irregular stromata, the superficial 

 portion flat, the ostiole minute and slightly depressed; spores 8, oblong, 9-13- 

 septate transverselv and 2-3-septate longitudinally, the cells cubical, 40-50 X 

 12-16 p. 



On trees, Florida. 



2. Laurera megasperma (Mont.) Riddle, Bull. Torr. Club 44:323. 1917. 



Trypethelium megaspermum Mont., Ann. Sci. Nat. Bot. II. 19:68. 1843. 



Thallus very thin, smooth to rough, ashy to pale yellow; perithecia small 

 to middle-sized, 0.4-1 mm. across, 1-several immersed in wartlike stromata, the 

 superficial portion flat, black; spores 2-4, oblong-ellipsoid, 33-43-septate trans- 

 versely and 3-5-septate longitudinally, the cells almost cubical, 150-240 X 24-36 fi. 



On trees, Florida. 



6. ASTROTHELIACEAE 



Thallus crustose, partly within the substratum, devoid of differentiation into 

 layers or showing a poorly developed upper cortex of coherent hyphae; perithecia 

 immersed, more or less radiately arranged, simple or united, the ostioles usually 

 converging, rarely terminal; paraphyses unbranched or branched and more or less 

 interwoven. 



The algal host is Trentepohlia. 



A. Spores brown, transversely several-septate 29. Pyrenastrum 



A. Spores brown, transversely and longitudinally septate .... 30. Parmentaria 



