LICHENS OF SANTA CRUZ PENINSULA 383 



Lichen saturnhiuni Smith, Trans. Linn. Soc. i : 84. I79^- 

 Leftogium saturninum Schaerer, Lich. Helvet. Spicil. 534. 

 1840, 



8. LEPTOGIUM MYOCHROUM TOMENTOSUM 



(Schaer.) Tuck. 



Thallu^ orbicular, flattish, much thinner than L,. satiirninuni ; 

 lobes large, round, somewhat plaited. Color greenish black 

 with very small black granules more or less thickly sprinkled 

 over the surface ; beneath pale, smooth, very minutely velvety 

 pubescent. Sterile. 



On trees. Rare. A very few specimens collected on Black 

 Mountain, at an elevation of 2200 feet. 



Identification by Dr. Hasse and the author ; no specimens 

 available to submit to Dr. Zahlbruckner. 

 Leftogiiim tomentostim Schaerer. 

 Leptogium myochroiini tomenioswn Tuck. Syn. N. Am. Lich. 



I : 166. 1882. 



XVn. Placodium (DC.) Naeg. & Hepp. 



Thallus typically crustaceous and lobate at the circumfer- 

 ence, or uniform ; very rarely suffruticose, as in the species de- 

 scribed below ; color usually yellow or orange. 



Apothecia generally scattered, but in the following species 

 terminal ; the disk usually yellow or orange. Spores ellipsoid, 

 polar-bilocular in the present species as is t3^pical of the genus, 

 simple, colorless. 

 Placodimn DeCandolle, Fl. Fr. 2: 377. 1805; Naegeli & 



Hepp in Hepp, Abb. u. Beschr. d. Spor. d. Flecht. Eur. pi. 



2, et passim. 1853. 



I. PLACODIUM CORALLOIDES Tuck. 

 Thallus slender, solid, cartilagineous, decumbent, forming 

 orbiculate, eventually indeterminate patches ; branches terete, 

 nodulose, blunt, sub-dichotomously divided, much intertangled ; 

 color bright yellow or orange, finally dark orange ; underneath 

 and basally grayish or blackening. Apothecia small to me- 

 dium, lateral or terminal, sub-pedicellate ; the rough, dark- 

 orange disk somewhat concave, becoming finally convex and 



