61. Chiodecton] 16. CHIODECTONACEAE 121 



1. Sarcographa tricosa (Ach.) Mull. Arg., Mem. Soc. Phys. Hist. Nat. Geneve 



29:63. 1887. 



Graphis tricosa Ach., Lich. Univ. 674. 1810. 



Thallus mainly or wholly within the substratum, indicated at the surface by a 

 whitish or brownish gray coloration ; stromata thin, scarcely raised, round to irreg- 

 ular, 2-4.5 mm. across, ashy white, blackish within; apothecia small to middle- 

 sized, elongated, 0.3-1 X 0.2-0.35 mm., immersed, usually many in each stroma, 

 much branched, the disk slightly concave to flat, dark brown to black; hypothe- 

 cium dark brown; spores 8, brownish, oblong-ellipsoid, 3-septate, 12-16 X 5-7 /x. 



On trees, from Maryland to Florida, and westward to Louisiana and Texas. 



2. Sarcographa labyrinthica (Ach.) Mull. Arg., Mem. Soc. Phys. Hist. Nat. 



Geneve 29:62. 1887. 



Glyphis labyrinthica Ach., Syn. Meth. Lich. 107. 1814. 



Thallus mainly or wholly within the substratum, indicated at the surface by 

 an ashy green to brownish coloration; stromata raised, round to irregular, 2-6 mm. 

 across, ashy white, black within; apothecia small to middle-sized, elongated, 0.3-1 

 X 0.2-0.3 mm., immersed many in each stroma, slightly curved, somewhat 

 branched, the disk slightly concave to flat, black; hypothecium dark brown; spores 

 8, brownish to brown, oblong-ellipsoid, 3- rarely 5-septate, 15-23 X 6-7.5 fx. 



On trees, Florida. 



3. Sarcographa medusulina (Nyl.) Mull. Arg., Flora 70:77. 1887. 

 Glyphis medusulina Nyl., Act. Soc. Sci. Fenn. 7:485. 1863. 



Thallus mainly within the substratum, indicated at the surface by an ashy 

 white to dull grayish coloration; stromata slightly raised, ashy white, black 

 within; apothecia small to middle-sized, elongated, 0.3-1.5 X 0.2-0.35 mm., im- 

 mersed many in each stroma, branched, the disk slightly concave to flat, black; 

 hypothecium dark brown; spores 8, brownish, oblong-ellipsoid, 3-septate, 16-20 

 X 6-9 \x. 



On trees, Florida. 



60. Medusulina Mull. Arg., Bull. Herb. Boiss. 2:93. 1894. 



Thallus crustose, superficial, smooth to rough, rudimentary, commonly devoid 

 of differentiation into layers, attached to the substratum by hyphal rhizoids; apo- 

 thecia middle-sized to large, clustered in more or less raised stromata, immersed 

 to superficial, round to oblong or irregular, branched, the disk closed to open, 

 more or less concave to flat, the exciple colored like the disk or lighter; hypothe- 

 cium and hymenium hyaline; paraphyses unbranched, free; asci oblong to clavate, 

 with the apical wall somewhat thickened; spores 1-8, hyaline, oblong-ellipsoid to 

 ellipsoid or fusiform, transversely and longitudinally septate, the cells spherical or 

 lenticular. 



The algal host is Trentepohlia. 



1. Medusulina texana Mull. Arg., Bull. Herb. Boiss. 2:93. 1894. 



Thallus thin, smooth to sometimes warty, ashy to pale yellowish or greenish 

 gray; apothecia middle-sized to large, 0.6-1.2 X 0.1-0.25 mm., erumpent and sur- 

 rounded by whitish, often sorediate areas of thallus, oblong to irregular, some- 

 times curved, rarely branched, the disk closed to open, concave to flat, black, the 

 exciple thin, whitish; spores 1, oblong-ellipsoid, 15-19-septate transversely and 

 5-7-septate longitudinally, 120-150 X 50-60 fx. 



On trees, Texas. 



61. Chiodecton Ach., Syn. Meth. Lich. 108. 1814. 



Thallus crustose, superficial, attached to the substratum by hyphal rhizoids; 

 apothecia grouped in a stroma, immersed or superficial, circular, elongated, radi- 

 ately or irregularly branched, the proper exciple well developed, brown to black, 



