168 29. HEPPIACEAE [106. Heppia 



var. pulvinatum (Hoffm.) Zahlbr., Cat. Lich. Univ. 3:142. 1924. 

 Collema pulvinatum Hoffm., Deutschl. Fl. 2:104. 1796. L.lacerum var. pul- 

 vinatum (Hoffm.) Mont. 

 Transforming the algal colony into a smaller, brownish, lobed body, the lobes 

 smaller, densely crowded with finely fringed edges, usually sterile. 



On humus, mosses, and dead pine leaves, Maine, Massachusetts, Minnesota, 

 and California. 



OTHER SPECIES REPORTED 



Leptogium fragile (Tayl.) Nyl. — California. 

 Leptogium intricatulum Nyl. — New Hampshire. 

 Leptogium microdium (Nyl.) Zahlbr. — Southern California. 

 Leptogium pulvillus Tuck. — Pennsylvania. 



29. HEPPIACEAE 



Thallus squamulose, foliose, or more or less fruticose, commonly differentiated 

 into upper and lower cortices, algal and medullary layers, sometimes more or less 

 plectenchymatous throughout, usually attached to the substratum at the center; 

 apothecia more or less immersed, the proper exciple indistinct, sometimes sur- 

 rounded by a thalloid one. 



The algal host is a blue-green, usually Polycoccus. 



A. Spores 8 in each ascus 107. Solorinaria 



A. Spores many in each ascus 106. Heppia 



106. Heppia Naeg., in Hepp, Spor. Flecht. Eur. pi. 7, f. 49. 1853. 



Thallus foliose, attached to the substratum by rhizoids, plectenchymatous 

 throughout, but differentiated into an upper cortex of 3 or more layers of hori- 

 zontally elongated cells, algal and medullary regions of loosely arranged and 

 vertically elongated cells, and a lower cortex of 1 or more layers of horizontally 

 elongated cells; apothecia minute to middle-sized, more or less immersed to adnate, 

 the disk more or less concave to flat or slightly convex, reddish brown to brown 

 and black, the exciple very thin to thin, colored like the thallus, sometimes want- 

 ing; hypothecium hyaline to brownish; hymenium hyaline or brownish above; 

 paraphyses unbranched, somewhat coherent; asci clavate to cylindrical; spores 

 many, hyaline, non-septate, spheroidal to oblong or ellipsoid. 



The algal host is usually Polycoccus. 



A. Spores subspherical or globose 



B. Thallus yellowish to olive-green 6. H. leptopholis 



B. Thallus olive-green to brownish 



C. Apothecia immersed, 1-8 in each squamule 9. H. Zahlbruckneri 



C. Apothecia immersed to adnate, 1 in each squamule 



D. Apothecia 0.4-0.75 mm. across 5. H. terrena 



D. Apothecia 0.1-0.25 mm. across 8. H. placodizans 



A. Spores subspherical to ovoid or oblong 

 B. Spores rarely more than 7 /x in length 



C. Thallus with sorediate and usually revolute margins . . . . 1. H. Guepini 

 C. Thallus not sorediate 



D. Squamules minute, crowded, subimbricate 2. H. Bolanderi 



D. Squamules small, not imbricate 



E. Margins entire to irregular 3. H. polyspora 



E. Margins irregular and lobulate-crenate 7. H. Hassei 



B. Spores 7-10 fi in length 



C. Thallus of small clustered squamules 4. H. deserticola 



C. Thallus of smaller, more scattered and 



depressed squamules 4. H. deserticola minor 



1. Heppia Guepini (Del.) Nyl., in Hue, Lich. Exot. 125. 1892. 



Endocarpon Guepini Del., in Duby, Bot. Gall. 2:594. 1830. Endocarpiscum 

 Guepini (Del.) Nyl. 



Thallus thick, composed of large, flat to variously irregular, olive-green to 

 brownish, foliose squamules with raised, sorediate, and usually revolute margins; 



