382 44. PHYSCIACEAE [ 173. Pyxine 



thin, colored like the thallus; hypothecium dark brown; spores oblong-ellipsoid, 

 sometimes slightly constricted at the septum, 9-14 X 5-7 /*. 

 On rocks, California. 



OTHER SPECIES REPORTED 

 Rinodina dirinoides Zahlbr. — California. 

 Rinodina succedens Nyl. — Southern California. 



44. PHYSCIACEAE 



Thallus foliose to fruticose, dorsiventral or radial, differentiated into well- 

 developed cortices of plectenchyma or interwoven hyphae, algal and medullary 

 layers, in the fruticose forms the medulla forming the central cylinder, attached to 

 the substratum by rhizoids; apothecia round, adnate to sessile, with well-developed 

 proper or thalloid exciple. 



The algal host is Protococcus. 



A. Upper cortex plectenchymatous 



B. The exciple colored like the thallu? 174. Physcia 



B. The exciple becoming black 173. Pyxine 



A. Upper cortex not plectenchymatous 175. Anaptychia 



173. Pyxine E. Fries, Syst. Orb. Veg. 267. 1825. 



Thallus foliose, more or less lobed and imbricated, commonly sorediate, closely 

 adnate, differentiated into a more or less well-developed plectenchymatous upper 

 cortex, algal and medullary layers, the lower surface more or less covered with 

 black or brownish black rhizoids; apothecia small to rarely middle-sized, sessile, 

 the disk flat to more or less convex, black or pruinose, the exciple thin, colored 

 like the disk, covered by a more conspicuous thalloid one, soon becoming black; 

 hypothecium dark brown to brownish black; hymenium brownish; paraphyses 

 unbranched, thickened and brownish at the apex; asci clavate; spores 8, brown, 

 oblong to ellipsoid, 1-3-septate. 



The algal host is Protococcus. 



A. Spores 1-septate 



B. Thallus small to middle-sized; spores not more than 23 fi in length 

 C. On trees; apothecia rarelv less than 0.8 mm. across 



D. Thallus smooth 3. P. cocoes 



D. Thallus smooth to wrinkled, or passing into a warty crust 



E. Thallus small, rarely bearing soredia 4. P. Meissneri 



E. Thallus larger, often bearing soredia 5. P. picta 



C. On rocks; apothecia 0.5-0.8 mm. across 6. P. Frostii 



B. Thallus middle-sized to large; spores 17-28 X 6-10 fi .... 1. P. sorediata 

 A. Spores 3-septate 2. P. Eschweileri 



1. Pyxine sorediata (Ach.) E. Fries, in Sagra, Hist. Cuba 188. 1842. 



Lecidea sorediata Ach., Syn. Meth. Lich. 54. 1814. 



Thallus middle-sized to large, closely adnate, smooth or wrinkled, greenish 

 gray to ashy or greenish, the lobes somewhat elongated, subdichotomously branched, 

 more or less imbricated, the ends round or crenate, usually more or less covered with 

 white or grayish soredia; black below, or brownish toward the margins, with black 

 rhizoids; apothecia small, 0.75-1.5 mm. across, the disk flat to convex, black or 

 rarely whitish pruinose, the exciple thin, colored like the disk; hypothecium brown 

 to blackish brown; spores oblong to ellipsoid, 1-septate, 17-28 X 6-10 [x. (Plate 

 46.) 



On trees and rocks, throughout the United States. 



