164 28. COLLEMACEAE [ 105. Leptogium 



tex plectenchymatous ; apothecia minute, 0.1-0.3 mm. across, adnate to sessile, 

 round, numerous, scattered or clustered, the disk concave to flat, brownish to 

 reddish brown or brownish black, bright reddish brown when moistened, the algoid 

 exciple thin to moderately thick, smooth to rarely somewhat rough or wavy; hypo- 

 thecium hyaline; spores ellipsoid to pointed-ellipsoid, 5-septate transversely and 

 1-2-septate longitudinally, the cells almost cubical, 18-25X8-10^, irregularly 

 arranged. 



On old wood, near Oxford, Ohio. 



10. Leptogium saturninum (Dicks.) Nyl., Act. Soc. Linn. Bord. 21:272. 1856. 

 Lichen satuminus Dicks., Fasc. PL Crypt. Brit. 2:21. pi. 6, f. 8. 1790. Collema 



saturninum (Dicks.) DC. L. myochroum (Ehrh. ) Nyl. L.myochroum var. 

 tomentosum (Hoffm.) Tuck. 



Transforming the algal colony into a large, irregularly lobed, smooth to 

 wrinkled and somewhat granulose, marginally ascending and imbricated, lead- 

 colored to greenish or blackish body; grayish to darker and densely tomentose 

 below; apothecia middle-sized, 0.7-2 mm. across, subsessile, the disk flat, reddish 

 brown, the algoid exciple thin, colored like the thallus, more or less irregular, often 

 granulose; hypothecium hyaline to cloudy; spores ellipsoid, 3-septate transversely 

 and partly 1-septate longitudinally, 20-29 X 7-10 fi. 



On trees and rocks, throughout the United States. 



11. Leptogium Burgessii (L.) Mont., in Webb & Berth., Hist. Nat. Canar. 3 2 : 



129. 1840. 



Lichen Burgessii L., Syst. Veg. ed. 13. 807. 1774. 



Transforming the algal colony into a large, loosely aggregated, smooth to gran- 

 ulose, grayish green to lead-colored or purplish brown, marginally crenate or cut- 

 lobed, imbricate, ascending body; ashy below and more or less covered with 

 delicate rhizoids; apothecia large, 1.5-4 mm. across, sessile, the disk concave to 

 flat, reddish to dark brown, the algoid exciple brown, moderately thick, irregularly 

 lobed; hypothecium hyaline or tinged brownish; spores ellipsoid, often pointed 

 toward the ends, 7-9-septate transversely and 3-4-septate longitudinally, 30-45 X 

 15-18 fi. 



On trees, New England, Virginia, and California. 



12. Leptogium Hildenbrandii (Garov.) Nyl., Act. Soc. Linn. Bord. 21:272. 



1856. 



Collema Hildenbrandii Garov., Lich. Prov. Comens. 1:3. 1837. 



Transforming the algal colony into a middle-sized to larger, round, irregularly 

 lobed, smooth to densely granulose, lead-colored to greenish black body, the lobes 

 rounded outward and irregularly cut at the margin; paler below, and wrinkled, 

 sometimes bearing clustered rhizoids; apothecia small to middle-sized, 0.5-1.75 

 mm. across, sessile, the disk flat to convex, brownish red to brown, the algoid 

 exciple colored like the thallus; hypothecium hyaline or tinged brownish; spores 

 ellipsoid, 3-septate transversely and becoming 1-septate longitudinally, 16-24 X 

 9-1 1 fi. 



On trees, New Mexico and California. Our specimens are sterile. 



13. Leptogium chloromelum (Swartz) Nyl., Syn. Lich. 1:128. 1858. 

 Lichen chloromelus Swartz, Fl. Ind. Ace. 3:1892. 1806. 



Transforming the algal colony into a middle-sized or larger, somewhat rigid, 

 strongly wrinkled, finally densely granulose, dark green to lead-colored body, with 

 ascending crenately margined lobes, the central lobes folded and curled; apothecia 

 small to middle-sized, 0.4-1 mm. across, sessile to subsessile, the disk concave to 

 flat, red to brownish red, the algoid exciple thin, colored like the thallus, wrinkled 

 to folded and granulose; hypothecium hyaline to cloudy; spores ovoid to ellipsoid- 

 pointed, 3-5-septate transversely and 1-septate longitudinally, 18-32 X 8-13 /x. 



On trees, rocks, and mosses, throughout the United States. 



