HASSE—LICHEN FLORA OF SOUTHERN CALIFORNIA. 8 
in the southern part, and considerably in excess of this in the moun- 
tain section, where at the highest points snow frequently lingers into 
June and July. In the second district the rainfall is very much less. 
Accurate meteorological statistics, however, for this and the moun- 
tain region are not available. 
In the following systematic treatment species cited from definite 
localities without mention of the collector’s name are either of com- 
mon occurrence locally or have been collected by the writer. In the 
case of certain common cosmopolitan species it has seemed unneces- 
sary to mention any specific localities. 
SYSTEMATIC TREATMENT. 
LICHENES, subclass ASCOLICHENES. 
KEY) TO ORDERS. 
Hymeniuio soft, globose or semiglobose, covered 
or inclosed by the perithecium, perforated by 
an apical pore or fissure ..........---.--.-.--- PYRENOCARPEAE (p. 3). 
Hymenium exposed, disk-shaped cece cece cece eee GYMNOCARPEAE (p. 14). 
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Order PYRENO CARPEAE. 
Thallus mainly crustaceous or squamose (the few foliose or fruticose forms not 
found within our limits); alge either bright green Chlorophycaceae (Pleurococcus, 
Palmella, Chroolepus alge), or blue green Cyanophycaceae (Nostoc or Sirosiphon 
alge); perithecium generally dark to black, brittle, globular (entire) or semiglobular 
(dimidiate), and wholly or partly immersed in the thallus; apical pore minute, 
punctiform or variously fissured; inclosed hymenial structures soft, gelatinous, with 
or without hymenial gonidia; paraphyses simple or branching, frequently gelatinous 
and indistinct and apparently absent; spermatia endobasidial or exobasidial. 
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KEY TO FAMILIES. 
Cavity of perithecium not divided by septa. 
Thallus with Pleurococcus or Palmella 
gonidia. 
Crustac@ous........ ees eee eee eee eee eee VERRUCARIACEAE (p. 3). 
Squamulose.........2.-.--- 2222s ee ee eee DERMATOCARPACEAE (p. 8). 
Thallus with Chroolepus gonidia, crusta- 
ceous; perithecium without septa...... PYRENULACEAE (p. 11). 
Thallus with Nostoc gonidia.......-.-...... PYRENIDIACEAE (p. 12). 
Cavity of perithecium completely or incom- 
pletely partitioned by septa..,.......-.--- MYCOPORACEAE (p. 13). 
VERRUCARIACEAE. 
Thallus crustaceous, ecorticate; symbionts Pleurococcus or Palmella gonidia; 
perithecium simple, erect, perforated vertically by the apical aperture; thecal con- 
tents soft; paraphyses and asci membranes often gelatinous, indistinct, the former 
at times apparently absent. Our species do not contain hymenial gonidia. 
b 
