ptychographa] graphidace.e 225 



innate, sessile, roundish or difform, plane, reddish or sordid- 

 yellowish-red, thinly margined ; hypothecium colourless ; para- 

 physes slender, subdiscrete, pale-brownish at the apices; spores 

 ellipsoid, 0,008-12 mm. lojig, 0,004-6 mm. tbick ; hymenial 

 gelatine bluish then violet with iodine. — Agyrium spilomaiicum 

 Anzi in Comm. Soc. Critt. Ital. ii. p. 20 (1864). 



The sorediate thallus, which, as noticed by Th. Fries, is often 

 sterile, apart from the other diagnostic characters, readily identifies 

 the plant. The apothecia, sparingly visible in the British specimen, 

 are either solitary or conglomerate, and in the latter case more or 

 less corrugate. 



Hah. On a decorticated fir tree in an upland mountainous district. 

 — B. M. Mar Forest, Braemar, Aberdeenshire. 



87. PTYCHOGRAPHA Nyl. in Flora Ivii. p. 315 (1874). 

 (PI. 24.) 



Thallus effuse. Algal cells Pahiella. Apothecia elongate, 

 compound, with 2 to 4 parallel hymenia ; margins prominent, 

 incurved ; hypothecium black, carbonaceous ; spores 8 in the 

 ascus, simple, colourless. 



Distinguished from all other genera of the Graphidacece by the 

 compound hymenia. 



1. P. xylographoides Nyl. /. c. — Thallus effuse, in thin 

 greyish- white spots or nearly obsolete (K — , CaCl — ). Apothecia 

 slightly prominent, plane above, margined, black, concolorous 

 within ; epithecium longitudinally 1- or 3-plicate, subincolorous ; 

 hypothecium and perithecium black; spores ellipsoid, 0,011-14 

 mm. long, 0,006-7 mm. thick ; hymenial gelatine wine-red with 

 iodine. — Cromb. in Journ. Bot. xii. p. 257, t. 150 (1874); 

 Leight. Lich. Fl. ed. 3, p. 392. 



Exsicc. Cromb. n. 192. 



Might at fhst sight be taken for Xylographa parallela^ which it 

 closely resembles in the parallel grouping of the apothecia. It is, 

 however, at once separated by the peculiar character of the hymenia. 



Hah. On a decorticated trunk of Pyrus Aucuparia in a subalpine 

 mountainous district. — B. M. Craig Calliach, Killin, Perthshire (the 

 only locality). 



88. ENCEPHALOGRAPHA Massal. Geneac. Lich. p. 13(1854). 

 Mclanospora Mudd Man. p. 226 (1861). (PI. 25.) 



Thallus effuse, crustaceous. Algal cells Palmella. Apothecia 

 sessile, usually in groups, elongate, roundish or angular, simple or 

 branched ; disc usually narrow ; hypothecium carbonaceous, black; 

 spores 5 to 8 in the ascus ; colourless to dark-brown, 1 -septate. 



E. cerebrina Massal. Misc. Lich. p. 49 (1856).— Thallus sub- 

 determinate, tnickish, tartareous, chalky -white. Apothecia black, 

 scattered or congregate^ sessile, oblong, roundish or angular, the 

 II. q 



