134 20. THELOTREMACEAE [74. Leptotrema 



3. Leptotrema monosporum (Nyl.) Mull. Arg., Bull. Soc. Bot. Belg. 31:35. 



1892. 



Thelotrema monosporum Nyl., Ann. Sci. Nat. IV. 15:46. 1861. 



Thallus thin, smooth to slightly rough, white to yellowish or ashy white; 

 apothecia small to middle-sized, 0.3-0.8 mm. across, immersed, the disk minute, 

 bordered by a firm, elevated, thalloid exciple, the proper exciple thin, black; spores 

 1, hyaline to brownish, oblong-ellipsoid, 17-35-septate transversely and 3-5-septate 

 longitudinally, 80-135 X 20-36 fi. 



On trees, Florida, Alabama, and Texas. 



4. Leptotrema Wightii (Tayl.) Mull. Arg., Flora 65:499. 1882. 

 Endocarpon Wightii Tayl., in Hook., Journ. Bot. 155. 1847. Thelotrema Wightii 



(Tayl.) Nyl. 



Thallus thin to moderately thick, smooth to minutely wrinkled, greenish gray 

 to ashy; apothecia small to middle-sized, 0.4-1 mm. across, immersed, the disk 

 minute, the proper exciple thin, black, the thalloid exciple thin, smooth, colored 

 like the thallus or lighter; spores 8, ovoid-ellipsoid, 3-6-septate transversely and 

 1-2-septate longitudinally, 14-26 X 10-14 /a. 



On trees, from South Carolina to Florida, and westward to Texas. 



5. Leptotrema santense (Tuck.) Zahlbr., Cat. Lich. Univ. 2:639. 1924. 



Thelotrema santense Tuck., Proc. Am. Acad. 5:406. 1862. 



Thallus thick, rough, sometimes crumbling, often bearing minute coralloid 

 branchlets, greenish gray to darker or ashy; apothecia small to middle-sized, 0.6-1.2 

 mm. across, immersed, the disk deeply concave to flat, black, often whitish pru- 

 inose, the proper exciple black, elevated, incurved and torn crenately, surrounded 

 by a heavy, irregular, thalloid one ; spores 8, ellipsoid, 2-5-septate transversely and 

 1- or rarely 2-septate longitudinally, 16-28 X 7-12 /a. 



On trees, South Carolina, Florida, Louisiana, and Alabama. 



6. Leptotrema laeviusculum (Nyl.) Zahlbr., Cat. Lich. Univ. 2:635. 1924. 



Thelotrema laeviusculum Nyl., Ann. Sci. Nat. Bot. IV. 19:335. 1863. 



Thallus thin to somewhat thick, rough, chinky and becoming areolate, greenish 

 gray to ashy; apothecia minute, 0.08-0.2 mm. across, immersed, the disk concave, 

 black, the proper exciple thin, black, surrounded by a thin thalloid one; spores 8, 

 oblong, 3-septate transversely and 1-septate longitudinally, 12-18X7-10//.. 



On trees, South Carolina and Louisiana. 



7. Leptotrema glaucescens (Nyl.) Mull. Arg., Flora 65:499. 1882. 



Thelotrema glaucescens Nyl., Ann. Sci. Nat. Bot. IV. 19:332. 1863. Thelotrema 

 compunctum var. glaucescens Nyl. 



Thallus thin, rough, chinky, greenish gray to ashy; apothecia minute to small, 

 0.2-0.6 mm. across, immersed, the disk concave to almost flat, black, whitish 

 pruinose, the proper exciple thin, whitish, surrounded by a thicker, irregular, 

 raised, thalloid one; spores 8, ellipsoid, 3-septate transversely and becoming 

 1-septate longitudinally, 10-16 X 6-9 /*. 



On trees, South Carolina, Georgia, Florida, Alabama, and Louisiana. 



8. Leptotrema heterosporum (Knight) Zahlbr., Cat. Lich. Univ. 2:635. 1924. 



Thelotrema heterosporum Knight, in Bailey, Syn. Queens. Flora Suppl. 1:72. 

 pi. 1, f. 2. 1886. L.mastoideum Mull. Arg. 



Thallus thin to somewhat thicker, smooth to rough, bearing minute coralloid 

 branchlets, greenish gray to ashy white; apothecia middle-sized to large, 0.8-2 mm. 

 across, immersed to superficial, the disk concave to flat, black or grayish pruinose, 

 the proper exciple thin, surrounded by a thicker, irregularly torn and crenate, 

 thalloid one; spores 8, ellipsoid, 3-septate transversely and 1-septate longitudinally, 

 17-23 X 7-10/*. 



On trees, Louisiana. 



