HASSE—-LICHEN FLORA OF SOUTHERN CALIFORNIA. 17 
KEY TO FAMILIES. 
Apothecia without margin........................ ARTHONIACEAE (p. 17). 
Apothecia margined (the margin rudimentary at 
times). 
Thallus crustaceous. 
Thallus ecorticate. 
Apothecia separate...............2005 GRAPHIDACEAE (p. 24). 
Apothecia confluent in a stroma....... CHIODECTONACEAE (p. 26). 
Thallus corticate above ................... DIRINACEAE (p. 27). 
Thallus fruticose -................ 022.202.2200. ROCCELLACEAE (p. 28). 
ARTHONIACEAE., 
Thallus crustaceous, uniform, with Palmella or Chroolepus alge; apothecia round, 
oval, or linear, entire or branching, separate or confluent in a stroma (the latter state 
not occurring with us); paraphyses branching and connected; spermatia exobasidial. 
KEY TO GENERA. 
Thallus with Palmella gonidia................0...22...-0005 ALLARTHONIA (p. 22). 
Thallus with Chroolepus gonidia. 
Spores parallel several locular.......................04- ARTHONIA (p. 17). 
Spores muriform.................-- cece eee cece ee eeeee ARTHOTHELIUM (p. 22), 
ARTHONIA Ach. 
Thallus crustaceous, thin, uniform or at the periphery approaching an effigurate 
state; apothecia immersed or sessile, roundish or irregularly stellate or elongated; 
paraphyses branching and mostly indistinct; asci pyriform, 8-spored; spermatia 
cylindric to elongate, straight or curved; spores bilocular to plurilocular, 
KEY TO SPECIES. 
Spores 2 or 3-locular. 
Growing on earth; apothecia round...................- 2. A. glebosa. 
Growing on bark. 
Apothecia round to ovoid or oblong. 
Sessile on thallus...............-.2.......----- 4. A. galactitella. 
Innate in thallus................2.-2.....-..--- 5. A. rhoidis. 
Apothecia not roundish, more or less angular. 
Brownish black..............2.22....-------+- 1. A. microspermella. 
Bluish black................--.-. wee eeeeeedas 3. A. subdispuncta. 
Spores 4 to 8-locular; growing on bark. 
Thallus thick, whitish, pulverulent. 
Apothecia some shade of brown; disk pruinose. 
Entire or nearly so in outline, 
Large.........2.-2-22.------------+------- 14. A. impolita. 
Smaller.................2.0--0e eee eee eee l4a, A. impolita chi- 
odectonoides. 
Not entire in outline. 
Deeply sinuate......ceeeceeeeeeeee eee eee 17. A. polygramma. 
Less deeply sinuate................------- 16. A. gyalectoides. 
Thallus thin, smooth, some shade of gray. 
Apothecia somewhat pruinose. 
Medium large..........2...2-2--20.-00--220--- 9. A. pruinosella, 
Very small... .... cc cece e ewww e cence eee e eee ll. A. subdiffusa. 
