LICHENS OF SANTA CRUZ PENINSULA 363 



Parniclia voiKsta Ach. Meth. Lich. 211. 1S03. 



Physcia vcnusta Nyl. Bull. Soc. Bot. Fr. 25 : 383,//. Jj. 1878. 



7. PHYSCIA MUSCIGENA (Ach.) Nyl. 



Thallus diffuse, spreading, irregular; the laciniate, numerous 

 lobes short, narrow, distinct, often upturned at the tip ; margins 

 more or less sorediate or powdery with confluent, sulphur-col- 

 ored soredia ; surface often with isidiose or cephaloid out- 

 growths. Medullary laj'^er usually greenish yellow or sulphur- 

 colored ; color brown, finally a very dark dull brown ; rarely 

 greenish ; usually only tips of lobes pruinose ; beneath white, 

 becoming very dark ; densely clothed with more or less hispid 

 black fibrils. Apothecia rare, scattered ; margin thick, becom- 

 ing sorediate. 



Common in the foothills on mossy sandstone and the trunks 

 of oaks. 



Pai'inelia inuscigcna Ach. Lich. Univ. 472. 1810. 

 Physcia imtscigena Nyl. Syn. Meth. Lich. i : 418. i860. 



8. PHYSCIA STELLARIS (L.) Nylander. 



Thallus smooth, appressed, stellate or irregular; lobes many- 

 cleft, sinuate, very close together; thickly sprinkled with small 

 white sub-epidermal spots ; neither pruinose nor sorediate ; 

 color white ; beneath white or pale, clothed more or less with 

 simple white fibrils. Apothecia black, usuall}^ pruinose ; mar- 

 gin entire. 



On stones and twigs ; not common. 

 Lichen stellaris Linn. Sp. PI. 2 : 1144. 1753- 

 Physcia stellaris Nyl. Syn. Meth. Lich. i : 424. i860. 



9. PHYSCIA AIPOLIA (Ach.) Nylander. 



Thallus orbicular, expanded, appressed; lobes much cleft, 

 sinuous, separate and distinct, or coalescent and imbricate ; very 

 thickly sprinkled with small white sub-epidermal spots; surface 

 smooth, without soredia; color white or bluish white.; beneath 

 dark or black, usually densely clothed with black hispid fibrils. 

 Apothecia numerous, usually bluish pruinose; disk brownish 

 black: margin thick, prominent, more or less crenate. Spores 



