142. Lecanora ] 38. LECANORACEAE 307 



lobed toward the circumference, light brown; apothecia small to middle-sized, 0.6- 

 1.5 mm. across, immersed to adnate, the disk slightly concave to flat, light to dark 

 brown, the exciple thin, colored like the thallus, becoming somewhat flexuous; 

 spores ellipsoid, 11-16 X 6.5-8.5 /x. 

 On rocks, Arizona. 



56. Lecanora versicolor (Pers.) Ach., Lich. Univ. 426. 1810. 



Lichen versicolor Pers., Ann. Bot. Usteri 7:24. 1794. L.muralis wax. versicolor 

 (Pers.) Tuck. 



Thallus thin, areolate toward the center, radiate-plicate toward the shortly 

 lobed margin, often dying in part and rejuvenating in the form of new lobes or 

 complete small thallus within the boundaries of larger partly dead old ones, yel- 

 lowish or whitish gray and sometimes more or less whitish powdery; apothecia 

 minute to small, 0.3-0.8 mm. across, partly immersed to adnate, the disk slightly 

 concave to flat, buff to darker brownish, the exciple thin, colored like the thallus, 

 becoming subcrenulate and flexuous, rarely and obscurely whitish powdery; spores 

 ellipsoid, 9-15 X 4.5-7 /*. (Plate 30.) 



On calcareous rocks, Iowa, Minnesota, Nebraska, Kansas, and Missouri. 



57. Lecanora muralis (Schreb.) Rabh., Deutschl. Krypt. Flora 2:42. 1845. 

 Lichen murdlis Schreb., Spic. Fl. Lips. 130. 1771. 



Thallus thin, closely adnate, greenish gray or sometimes yellowish or brownish, 

 the central portions more or less areolate or crenate-scaly, long- or shorter-lobed 

 toward the circumference, and the margin deeply wavy or irregularly crenate; 

 apothecia small to middle-sized, 0.65-2 mm. across, adnate to subsessile, the disk 

 flat, yellowish to tawny brown, the exciple thin, colored like the thallus, becoming 

 crenate and flexuous; spores ellipsoid, 9-15 X 4.5-7 ll. 



On rocks, throughout the United States. 

 var. Garovaglii (Koerb.) Tuck., Syn. N. A. Lich. 1:184. 1882. 



Placodium Garovaglii Koerb., Par. Lich. 54. 1865. L. Garovaglii (Koerb.) 

 Zahlbr. 



Thallus lobes elongated, flexuous, convex, radiately folded. 



On rocks, Minnesota, Nebraska, and Nevada. 



var. saxicola (Poll.) Tuck., Syn. N. A. Lich. 1:184. 1882. 

 Lichen saxicola Poll., Hist. Plant. 3:225. 1777. Parmelia saxicola (Poll.) Ach. 



L. saxicola (Poll.) Ach. 

 Thallus better developed, showing more tendency toward brown coloration, and 

 more flattish lobes; apothecia less closely attached to the thallus. 



On rocks, throughout northern United States, and southward in the mountains. 



58. Lecanora diffracta Ach., Lich. Univ. 432. 1810. 



Lichen diffractus Ach., Lich. Suec. 63,64. 1798. L.muralis var. diffracta (Ach.) 

 Rabh. L. saxicola var. diffracta (Ach.) Jatta. 



Thallus mainly or wholly areolate, or the margins short-lobed, yellowish brown 

 or reddish and darker, the areoles and squamules usually black-edged; apothecia 

 small to middle-sized, 0.6-1.5 mm. across, adnate, the disk flat to slightly convex, 

 brown or rarely reddish brown, the exciple thin, colored like the thallus, crenate 

 or minutely flexuous; spores ellipsoid, 9-14 X 4-6 /t. 



On rocks, Minnesota and California. 



59. Lecanora lentigera (Web.) Ach., Lich. Univ. 423. 1810. 

 Lichen lentigerus Web., Spic. Fl. Goett. 192. 1778. 



Thallus moderately thick, greenish to yellowish white, commonly more or less 

 whitish pruinose, chinky to subareolate toward the center, deeply wavy and cre- 

 nately lobed toward the circumference; apothecia small to middle-sized, 0.6-2 mm. 

 across, adnate, clustered, the disk flat, buff-colored, the exciple thin, colored like 

 the thallus; spores ellipsoid, 9-13 X 4.5-5.5 ll. 



On soil, Nevada, Colorado, Nebraska, and Montana. 



