THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 1 39 



rocks. Some species always sterile in temperate regions and often 

 difficult to determine. 



KEY TO SPECIES. 



A. On trees. 



B. Dark green to black; smooth beneath; thallus fenestrate, wrinkled, 



ridged, isidiose i. chloromelutn stellans 



BB. Lead-color to blackish green. 



C. Beneath fleecy with long white or brown fibrils ... 2. hildebrandii 

 CC. Beneath covered with minute velvety pubescence. 3. saturninum 

 A A. On earth, moss, or rocks. 



D. On limestone only; thallus thick, plicate, orbiculate. . . .4. plicatile 

 DD. Not on limestone. 



E. Thallus small to minute. 



F. Thallus small, foliaceous, rather entire 5. scotinum 



FF. Thallus minute or microscopically foUaceous to crustose. 



G. Thallus irregularly cut and divided 6. tenuissimum 



GG. Thallus chaffy or scurfy, areolate, wine-red with I. 



7. rhy par odes 

 EE. Thallus medium size to large. 

 H. Thallus red-brown, chestnut, or lead-color; lobes narrowed 



^vith erect corniculate tips 8. palniatum 



EH. Color black. 

 /. Lobes erect, crenate, narrowed, complicate. . .9. calif ornicum 

 II. Thallusfiat,expanded, more or less orbicular. .. 10. />/a^>'«MW 



I. LEPTOGIUM CHLOROMELUM STELLANS Tuck. 



Lichen chloromelos Swartz, Fl. Ind. Occident. 3: 1892. 1806. 

 Leptogium chloromelum Nyl. Syn. Meth. Lich. 1: 128. i860. 

 Leptogium chloromelum stellans Tuck. Syn. N. Am. Lich. I: 163. 



1882. 

 Leptogium chloromelum stellans Herre, Proc. Wash. Acad. Sci. 7 : 382. 



1906. 



Thallus orbicular, becoming indeterminate, medium to very large, 

 more or less fenestrate, laciniate; lobes usually narrow, irregular, 

 more or less imbricate or coalescing; surface striate, wrinkled and 

 ridged, the ridges densely covered with black isidiose granules, or by 

 cristate-lacerate isidiose lobules; color dark green, plumbeous, or 

 black; beneath paler, wrinkled; rarely a very minute down sparingly 

 present. 



Sterile. 



Common on trees; reaching its maximum development at an alti- 

 tude of from 500 to 800 feet, the loosely connected thallus often 4 or 

 5 inches in diameter. 



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



