96 IS. GRAPHIDACEAE [49. Xylographa 



B. Spores septate 



C. Paraphyses unbranched and not interwoven 



D. Spores with cylindrical or cubical cells 52. Melaspilea 



D. Spores with lenticular cells 



E. Spores transversely several-septate 53. Graphis 



E. Spores transversely and longitudinally septate . . . 55. Graphina 

 C. Paraphyses branched and interwoven 



D. Spores with cylindrical or cubical cells 



E. Parasitic on lichens 51. Opegraphoidea 



E. Not parasitic on lichens 50. Opegrapha 



D. Spores with lenticular cells 57. Helminthocarpon 



A. Spores brown 



B. Spores transversely several-septate 54. Phaeographis 



B. Spores transversely and longitudinally septate .... 56. Phaeographina 



49. Xylographa E. Fries, Sum. Veg. Scand. 372. 1846. 



Thallus wholly within the substratum, or appearing above as minute warts or 

 as soredia or soralia; apothecia erumpent, round, elongated, or irregular, usually 

 straight and unbranched, the proper exciple usually dark-colored, the disk closed 

 or more or less open; hypothecium hyaline to brown; asci clavate; paraphyses 

 seldom branched, several-celled, with thin transverse walls; hymenium hyaline; 

 spores 8, non-septate, hyaline, usually ellipsoid; commonly on old wood. 



The algal host is Palmella. 



A. Spores 14-25^ in length 3. X. disseminata 



A. Spores not more than 16 /u. in length 



B. Apothecia reaching 1-1.5 mm. in length 1. X. abietina 



B. Apothecia not more than 0.5 mm. in length 



C. Apothecia round to oblong 2. X. hians 



C. Apothecia round to irregular and sometimes branched . . 4. X. opegraphella 



1. Xylographa abietina (Pers.) Zahlbr., Cat. Lich. Univ. 2:151-153. 1924. 

 Hysterium abietinum Pers., Obs. Mycol. 1:31. 1796. X. parallela (Ach.) Behlen 



& Desberg. 



Thallus within the substratum and showing at the surface as a whitish colora- 

 tion, or appearing above the surface as minute and uncertain whitish spots; apo- 

 thecia minute to becoming long and narrow, 0.4-1.5 X 0.15-0.2 mm., straight, 

 pointed at the ends, immersed, lying parallel in the substratum, the disk closed 

 to open and concave to fiat, black, the exciple thin, colored like the disk, rarely 

 disappearing; spores ellipsoid, 9.5-15 X 5-6.5 \x. 



On old wood, from New England westward to Washington. 



2. Xylographa hians Tuck., Syn. N. A. Lich. 2:113. 1888. 



Thallus usually within the substratum, indicated at the surface by a grayish 

 white coloration, but rarely showing minute, superficial granules; apothecia minute, 

 0.3-0.5 X 0.15-0.2 mm., adnate, scattered or clustered, circular to oblong or broad- 

 ly ellipsoid, the disk closed to open and concave to flat, brown to black, the 

 exciple becoming thin, colored like the disk or slightly darker; spores oblong- 

 ovoid, 9-14 X 5-7 ix. 



On old wood, Washington and Oregon. 



3. Xylographa disseminata Willey, in Tuck., Syn. N. A. Lich. 2:112, 113. 1888. 

 Thallus thin, continuous or scattered, greenish gray to ashy, composed of 



minute, spheroidal granules; apothecia minute, 0.2-0.4 X 0.2-0.25 mm., adnate. 

 circular to irregular, ellipsoid or oblong, the disk closed to open and concave to 

 flat, dark brown to black, the exciple black, becoming thin; spores oblong, some- 

 times reported 1-3-septate, 14-25 X 4-6 (x. 

 On old wood, New England. 



4. Xylographa opegraphella Nyl., Mem. Soc. Sci. Nat. Cherb. 5:128. 1857. 

 Thallus becoming thick, rough and warty, greenish gray to pale brownish, 



rarely disappearing; apothecia minute, 0.2-0.3 X 0.1-0.2 mm., partly immersed to 



