THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 251 



Apothecia from innate soon sessile, small or medium size, plane, 

 the persistent thalline margin thick, entire, sometimes wavy, often 

 inflexed; brownish black to black; paraphyses coherent, their tips 

 not much enlarged; epithecium dark blackish brown; thecium blue 



9 *3 

 with I; spores thick- walled, blunt, ellipsoid, Q _ 22 P* 



On sandstone in the mountains, apparently not very abundant. 

 Widespread throughout the north temperate zone. 



6. RINODINA HALLII Tuck. 

 Rinodina hallii Tuck. Syn. N. Am. Lich. I: 208. 1882. 



Thallus determinate, bounded by a conspicuous, broad, black 

 hypothallus, uniform, but soon chinky areolate, rather thin; color 

 varying from pale green-brown to umber, the dark forms most com- 

 mon; KOH-; CaCl 2 O 2 -. 



Apothecia numerous but not crowded, closely appressed but 

 hardly innate even when very young, from small to rather more than 

 medium size; the disk plane when very small, but soon convex, at 

 length strongly so, bordered by a thin, entire, concolorous proper 

 margin which is usually persistent, though sometimes excluded; 

 brownish black to black, occasionally partially covered with a thin 

 white bloom; paraphyses coherent, their enlarged tips yellow or yel- 

 lowish brown; epithecium brown; hypothecium clear; thecium deep 



blue with I; spores thin- walled, ellipsoid to irregular, r ' ^. 



On the bark of various trees, but abundant and conspicuous on 

 oaks; in the mountains at 1500 feet and above, and also in deep, dark 

 canons beside perennial streams as low as 600 feet. 



The more or less orbiculate thallus often spreads extensively and 

 becomes effuse by the union of several plants. 



There seem to be no published records of its occurrence outside 

 California and Oregon. 



Named for Elihu Hall, an Illinois botanist and collector who also 

 collected extensively in the west and sent Tuckerman his type speci- 

 mens. 



Proc. Wash. Acad. Sci., May, 1910. 



