THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 197 



Thallus narrow, lobed and deeply dissected; smooth above; the 

 lobes sinuately pinnatifid, their tips rounded or crenate, some- 

 times sorediate; centrally becoming much complicate and imbri- 

 cate; margin fringed with long, black, conspicuous cilia. Beneath 

 black and densely clothed with long black fibrils. Surface a dull 

 pearly gray, varying to a slate gray; KOH yellow; medulla red 

 withKOH;CaCl 2 O 2 -. 



Apothecia not known. 



This distinct Parmelia occurs only on earth in the crevices of 

 sandstone in Pilarcitos Creek Canon, about two miles from the 

 Pacific, at an altitude of 200-300 feet, and is rather abundant at 

 that locality. 



5. PARMELIA TILIACEA (Hoffm.) Ach. 



Lichen tiliaceus Hoffmann, Enum. 26, pi. 16, f. 2 } 1784; (in part;. 

 Parmelia tiliacea Ach . Me th . Lich .215. 1 803 . 

 Parmelia tiliacea Tuck. Syn. N. Am. Lich. I. : 57. 1882. 

 Parmelia tiliacea Herre, Proc. Wash. Acad. Sci. 7: 353. 1906. 



Thallus much narrowed, membranaceous, often suborbicular; 

 smooth, becoming finely wrinkled; closely adherent to the sub- 

 stratum; lobes contiguous, often subimbricate, sinuous, deeply 

 incised; margins crenate or rounded; color gray, varying from nearly 

 white to green, but always of a peculiarly bright/clean appearance; 

 beneath black; densely clothed with small black fibrils; KOH 

 yellowish; medulla red with CaCl 2 O2. 



Apothecia abundant, mostly central; disk bright chestnut; margin 

 entire, crenate, or crenulate, or even lobed; spores small, ellipsoid 



c- _ yl 



to rounded-ellipsoid, ~ ~ V- 



This beautifully colored bark-dwelling lichen, found in every 

 quarter of the globe, is very abundant with us on trees at an alti- 

 tude of 2000 feet and upward, though it descends occasionally to 

 much lower altitudes. Wherever found it is in full fruit. 



6. PARMELIA BORRERI Turn. 



Parmelia borreri Turner, Trans. Linn. Soc. 9: 148. pi. 13. f. 2. 1808. 

 Parmelia borreri Tuck. Syn. N. Am. Lich. I: 58. 1882. 



