320 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Here may be cited also: Cummings, Williams & Seymour, Dec. N. Amer. Lich., 

 no. 156, Mount Lafayette, N. II.; Cummings & Seymour, Dec. N. Amer. Lich., no, 60, 

 Columbia Falls, Montana. 



Explanation of Plate 71.— a, (Left-hand column) under surface of thallus; b, (right-hand column) 

 upper surface, same specimens. Material from Reno, Nevada. All scale 2. 



11. Gyrophora erosa (Weber) Ach. Meth. Lich. 103. 1S03. 

 Lichen erosus Weber, Spic. Fl. Goett. 259. 1778. 

 tlmbilicaria erosa Tuck. Syn. N. Amer. Lich. 1: 86. 1882. 



Thallus of moderate size, one-leaved, thin, rigid, the lobes few and rounded; mar- 

 gin very irregular, as if torn or gnawed; surface irregularly wrinkled and folded, 

 much dissected by intricate black, indented lines and chinks, which resemble the 

 sutures in a skull, these markings often passing into perforations and crevices cutting 

 entirely through the thallus; color varying from clear clay brown to blackish brown; 

 under side more or less radiately ridged, the ridges often foraminous, becoming ragged 

 or finally passing into laciniate fibrils; usually minutely granulosc, smooth, pale 

 brown or blackish; apothecia at first small, innate or plane, variously shaped, with 

 a thin margin; soon prominent, convex, plicate, the margin finally disappearing 

 and the apothecia moderately large; paraphyses short, slender, mostly coherent; 

 thecium greenish blue, soon changing to tawny or red brown with iodine; spores color- 



less, ellipsoid, ^~^al>-\ according to Tuckerman "fuscescent or decolorate, q-pr^i." 



Collected on rocks at Yosemite by Dr. II. E. Hasse, at an altitude of about 1,540 

 meters, and by me in the Sierras east of Truckee at 2,000 meters. As I have collected 

 it also at Reno, Nevada, we may safely say that it occurs from the Lake Tahoe region 

 northward. Other specimens were examined from Lake Fend d' Oreille, Idaho, 

 where it is said to be abundant on granite ledges, and from Great Slave Lake, British 

 America. I also found it mixed with herbarium specimens of Gyrophora hyperborca, 

 from Columbia Falls, Montana. 



12. Gyrophora phaea (Tuck.) Herre, Proc. Washington Acad. Sci. 7: 366. 1906, 



Plate 72. 

 Umbilicaria phaea Tuck. Lich. Calif. 15. 1866; Syn. N. Amer. Lich. 1: 86. 1882. 

 Thallus usually quite small or medium, rarely becoming large, one-leaved (occa- 

 sionally polyphyllous); upper surface smooth, brown, but varying from greenish or 

 grayish to olive and dark tawny brown; under surface without fibrils and granular, 

 usually darker brown than the upper surface, or even blackish, but sometimes paler, 

 with a pale bloom; apothecia numerous, black; at first innate, but finally prominent, 

 angular or rounded and plicate; thecium brown with iodine, the spores turning a 

 faint greenish yellow; spores simple, colorless to brown, variously arranged in the asci, 

 ir -1 5-8 8-10 



ellipsoid, io=l3^ an <*T3=T6''' 



The commonest and most characteristic Californian representative of the family. 

 According to Tuckerman found only between 300 and 1,000 meters altitude, but really 

 extending much above and below these limits. In the Santa Cruz Mountains and 

 in Alum Rock Park near San Jos6 it occurs at about 90 meters above sea level, while 

 I have collected it in the Sierra Nevada Mountains along the Truckee River and in 

 the desert about Reno, Nevada, at altitudes of from 1,650 meters to 2,000 meters. 

 In the Tehachepi Mountains it occurs at an altitude of 1,700 meters, according to 

 Doctor Hasse. 



This is one of the hardiest and most successful xerophytes known. In the deserts 

 of western Nevada where the rainfall is but 8 to 10 inches it grows on the most exposed 

 parts of the south side of bare cliffs and detached bowlders hung high above the soil, 

 where it would seem impossible for any plant to exist. In such places it is usually 

 very small and becomes practically a crustaceous or subcrustaceous lichen which 



