24 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
about 3-septate; ascus membrane staining a pale vinous red with iodine, the spores 
rich yellow, the other thecial structures blue. 
On Platanus and Heteromeles in the Santa Monica Mountains and on oak bark on 
Santa Catalina Island. 
GRAPHIDACEAE. 
Thallus crustaceous, attached to the substrate by medullary hyphe; gonidia con- 
sisting of Palmella or Chroolepus; apothecia normally elongated, not combined in a 
stroma, with a proper margin; disk rimeform; paraphyses simple, branched or 
unbranched, generally distinct. 
Only one genus as yet found within our limits. 
OPEGRAPHA Humb. 
Apothecia with a proper margin, innate, appressed or sessile, mostly elongate, 
lirelleeform ; disk rimeeform or slightly dilated; hypothecium dark or pallid; paraphyses 
branched and intertwining; asci clavate or oblong; spores in 8’s, ovoid, oblong to fusi- 
form, colorless, parallel-plurilocular with cylindric cells; sterigma simple; spermatia 
oblong, straight or curved. 
Our species belong to the section Euopegrapha Muell. Arg., the margin brittle, 
carbonaceous, continuous with the hypothecium (as seen on a transverse section of 
an apothecium), 
KEY TO SPECIES, 
Substratum rock; thallus white.............................. 1. O. chevallieri. 
Substratum bark. 
Spores 4 or 5-locular. 
Apothecia small. 
Straight or curved... ....2.....0..22..-.0.02.-. 9. O. umbellularve. 
Ovate.... 2.222... eee cece eee 2. O. atra lichenoides. 
Apothecia larger. 
Oblong... .- 22.2... 3. O. prosiliens. 
Linear, straight... 2.2.20... 00. e eee ce eee eee 4. O. atrorimalis, 
Spores 6-locular. 
Apothecia small. 
Round to ellipsoid.....-....0.00..0000.00....... 5. O. pulicaris. 
Numerous, round to oblong and linear............ 8. O. vulgata, 
Apothecia larger. 
Linear-elongate.-. 2.2.20... 000000. 0. 2 ec eeeeee. 6. O. rimalis. 
Fusiform, acute, black..........2.02....0...--.. 7. O. diaphora. 
1. Opegrapha chevallieri (Leight.). 
Opegrapha saxicola chevallieri Leight. Lichenfl. Brit, ed. 3. 402. 1879. 
Thallus white, furfuraceous, moderately thick, continuous to finely rimose, bor- 
dered by a thin black line, KHO—, Ca(ClO).--red; apothecia black, straight or 
curved, flexuose, mostly crowded and even contiguous; epithecium rimeform or 
slightly dilated and then flat, black, under the microscope brown black, less dark 
than the hypothecium; thecium 80 #1 high, dingy white, with iodine stained a deep 
orange; spores in 8’s, ellipsoid, 12 to 14 # long by 3.5 to 4 we thick, 
Newport Bluffs on sandstone; Santa Catalina Island on argillaceous rock. 
2. Opegrapha atra lichenoides Pers. 
Only the forma chlorina Jatta represented in our area, 
Thallus pale, dingy yellowish greenish, smooth ; apothecia small, ovate to roundish, 
the proper margin finally nearly obsolete and the disk greenish-pruinose; epithecium 
granulose, greenish brown to dark brown; thecium 88 to 90 “high, colorless, with iodine 
