60 5. TRYPETHELIACEAE [26. Melanotheca 



the wall thin, complete, the ostiole minute, slightly depressed; spores oblong- 

 ellipsoid, 7-9-septate transversely and 1-2-septate longitudinally, 18-28 X 7-9 /a. 

 arrangement obliquely uniseriate. 

 On trees, southern states. 



6. Anthracothecium mucosum (Vainio) Zahlbr., Cat. Lich. Univ. 1:464. 1922. 



Bottaria mucosa Vainio, Hedwigia 38:257. 1899. 



Thallus of medium thickness, whitish to pale olive-green, smooth and shining, 

 partly bordered by a blackish hypothallus; apothecia middle-sized, 0.5-0.7 mm. 

 across, immersed to emergent, convex, dark brown to blackish, the wall complete, 

 black, thin, the ostiole inconspicuous but opening finally; asci cylindrical; spores 8, 

 light brown, oblong-fusiform, 7-9-septate transversely and 1-3-septate longitudi- 

 nally, 35-50 X 12-20 [i, arrangement obliquely uniseriate. 



On trees, Florida. 



5. TRYPETHELIACEAE 



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

 of differentiation into layers, or rarely showing some differentiation; perithecia 

 more or less immersed, usually several in each stroma, the ostiole terminal; paraph- 

 yses unbranched and free, or branched and more or less interwoven. 



The algal host is Trentepohlia. 



A. Spores with lenticular cells 



B. Spores hyaline 27. Trypethelium 



B. Spores brown 26. Melanotheca 



A. Spores with cylindrical cells 28. Laurera 



26. Melanotheca Fee, Suppl. Essai Crypt. 70. 1837. 



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; perithecia minute to small, several to many immersed 

 in each stroma or rarely solitary in stromatic elevations, the wall complete, the 

 superficial portion convex or depressed, the ostiole minute, rarely visible; hypothe- 

 cium hyaline to brown; hymenium hyaline or brownish above; paraphyses un- 

 branched and free or branched and netlike interwoven; asci cylindrico-clavate ; 

 spores 8, brown, ellipsoid to oblong-ellipsoid or fusiform, obliquely uniseriately to 

 irregularly arranged, 3-several-septate, the cells lenticular. 



The algal host is Trentepohlia. 



A. Spores more than 18/i in length 



B. Thallus ashy to dull yellowish 4. M. concatervans 



B. Thallus more or less reddish brown 



C. Perithecia minute, not more than 0.2 mm. across ... 2. M. subincruenta 



C. Perithecia small, more than 0.2 mm. across 1. M. cruenta 



A. Spores not more than 18 fi in length 3. M. aggregata 



1. Melanotheca cruenta (Mont.) Miill. Arg.. Engl. Bot. Jahr. 6:397. 1885. 



Trypethelium omentum Mont., Ann. Sci. Nat. Bot. II. 8:537. 1837. 



Thallus very thin to thin, smooth to slightly rough, greenish to reddish brown; 

 perithecia minute to small, 0.3-0.8 mm. across, heaped together in a stroma, or 

 rarely solitary in stromatic elevations, the superficial portion convex, reddish brown 

 to black, the wall thin, black, complete, the ostiole minute, rarely visible; spores 

 3-septate, oblong-ellipsoid, 22-30 X 9-14 /x. 



On trees, from New Jersey to Florida and westward to Texas. 



2. Melanotheca subincruenta (Nyl.) Zahlbr., Cat. Lich. Univ. 1:483. 1922. 



Trypethelium subincruentum Nyl., Lich. Jap. 109. 1890. 



Thallus very thin, smooth to slightly rough, ashy to reddish brown; perithecia 

 minute, 0.06-0.2 mm. across, heaped together in irregular, reddish stromata, the 



