THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 205 



Apothecia usually abundant, medium to large; sub-pedicellate, 

 top-shaped and cup-like, becoming plane or even convex, when 

 the margin disappears; margin entire, crenulate, or lobulate; disk 



4-6 

 chestnut; often perforate; spores ellipsoid, /^. 



On trees, shrubs, and fences. A lichen of North and Central 

 America, and also found in Australia, Tasmania, and New Zealand. 



Very abundant along the summit of the range and extending down- 

 ward nearly to sea-level. Especially fine on Sequoia sempervirns 

 and Pseudolsuga taxifolia, being a characteristic lichen of the red- 

 wood forest. 



L. Cetraria Acharius. 



Cetraria Ach. Meth. Lich. 292. 1803, in part. 

 Cetraria Ach. Lich. Univ. 96. 1810. 



Thallus fruticose, or in most of our species expanded foliaceous 

 with lobes more or less ascendant, narrowed and elongate; both 

 sides with cortex; medullary layer cottony; color very variable, 

 green, white, yellow, brown, and black. 



Apothecia, except in number one, darker and of a different color 

 from that of the thallus; terminal or marginal; asci 6-8 sporous; 

 spores simple, ellipsoid, colorless; paraphyses simple, or branched 

 and conglutinate, septate. 



About fifty species of earth and bark lichens, characteristic of 

 alpine and arctic regions and the cooler parts of the temperate 

 zone. 



KEY TO THE SPECIES. 



A. Thallus black or greenish black i. calif ornica 



AA. Thallus variously colored. 

 B. Thallus not green or pale. 



C. Thallus yellow 2. juniperina 



CC. Thallus brown; lobes with white sorediate edges; always 



sterile 3. chlorophylla 



BB. Thallus green or pale. 



D. Foliaceous; green, more or less black basally beneath; edges 



dissected 4. glauca 



DD. Fruticose; lobes long, narrow, ascendant or pendulous. 



E. Sterile; lobes broad, black beneath 5. tuckermani 



EE. Apothecia abundant, terminal; lobes white beneath. 



6. lacunosa stenophylla 



