18 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Spores 4 to 8-locular; growing on bark—Continued. 
Thallus thin, smooth, some shade of gray—-Continued. 
Apothecia not pruinose. 
Outline entire, round to roundish. 
Large, prominent.....................-.-.- 7b. A. radiata swartz- 
iana. 
Small, less prominent. 
Not innate in thallus. 
Crowded, black when moist....... 15. A. lecanactidea, 
Not crowded. 
Black when moist...... weeeeee 12. A. punctiformis. 
Gray when moist ......... .. 10. A. diffusa. 
Innate in thallus...................... 18, A. epipastoides. 
Outline not entire. 
Stellate-radiate............2.2.--.--2020005- 7. A. radiata. 
Elongate-linear. 
Conspicuously branching and curved.. 7a. A. radiata angus- 
tata. 
Not conspicuously branching.......... 8. A. stictella. 
Not elongate, short-linear................- 6. A. tetramera. 
1. Arthonia microspermella Willey. 
Thallus whitish or silver gray, thin, effuse; apothecia small, round or oblong, nu- 
merous, brownish black; asci oblong-ovoid to subglobular, 36 to 40 » long, 18 to 20 u 
thick; spores in 8’s, colorless, 2 or 3-locular, 13 to 14 « long, 4 to 4.5 w# thick; hymenial 
gelatine blue with iodine, the asci and contents yellow. 
On Juglans californica, in canyons of the Santa Monica Mountains, A typespecimen 
not being available for comparison, the determination of the Californian lichen is 
subject to correction. 
2. Arthonia glebosa Tuck. 
Thallus thickish, of bullous, separate or connected and plicate, convex and rounded, 
pale dun colored squamules; apothecia black, roundish or oblong, convex, smooth, 
interspersed and becoming conglomerate between the thalline squamules; epithecium 
subcontinuous, light brown; thecium light brown, 48 to 52 # high; hypothecium 
dark brown and thick; paraphyses intricately interwoven; asci subinflated-clavate, 
the membrane slightly thickened above, 36 to 38 » long, 12 to 15 » thick; spores in 8’s, 
12 to 16 « long, 4 to 5 » thick, bilocular, the upper loculus round or ovoid, the lower 
narrower and slightly longer; hymenial gelatine with iodine orange to copper brown. 
A most singular-appearing Arthonia. 
‘ Mesas on earth. Collected by ©. R. Orcutt in Lower California. 
3. Arthonia subdispuncta Nyl.; Hasse, Bull. Torrey Club 24: 448. 1897, 
Thallus sordid white, subfarinaceous, effuse, hypothallus pale; apothecia bluish 
black, small, angular, oblong or irregularly round, about 0.1 mm, wide, sessile or 
subinnate; epithecium coarsely granulose, bluish gray; thecium colorless 28 to 30 4 
high; paraphyses obscure; asci broadly spatulate to pyriform, 30 to 34 4 long, 16 y 
thick; spores oblong-ellipsoid, bilocular, not constricted, attenuate at one end, the 
other end blunt, 11 » long, 4 « thick; hymenial gelatine with iodine pale yellow. 
On caudex of Leptosyne gigantea; beach bluffs at Point Dume, Santa Monica Moun- 
tains. Type deposited in the U. 8. National Herbarium; duplicate in herb. Hasse. 
4. Arthonia galactitella Nyl. 
Thallus forming cream-colored spots, irregular in outline and 1 to 2 cm, wide, finely 
furfuraceous; apothecia numerous, small, slightly erumpent, flat, somewhat pruinose, 
round, or, as if by aggregation of several, oblong; asci oblong-ovate; membrane thick- 
