254 GKAPHIDKI [PIIiKOGRAPHIS 



Leighton, Smithii is marked by the more (Iceply-immcrsed apothecia 

 which branch at an obtuse angle, in this respect differing from 

 f. acuta in which the angle is acute. Usually the carbonaceous wall 

 is thinly developed at the base of the apothecium, but in some forms 

 it is thicker, and occasionally there is a gap, observable in section with 

 the microscope, causing the apothecium to appear semidimidiate. 



Hah. On trees. —Distr. In wooded regions, chiefly in S. England 

 and S. Ireland. — B. M, Guernsey ; Eozel, Jersey ; Hustyn Wood, 

 Bodmin, Cornwall ; Carisbrookc, and near Shanklin, I. of Wight ; 

 Totnes, Torquay, near Becky Falls, Ivy Bridge and Ullacombe, Devon ; 

 Southton Common, Somerset ; Stoney Cross, near Bartley Lodge, 

 Brockenhurst, and near Lyndhurst, New Forest, Hants ; Ardingly, 

 St. Leonard's, Tunbridge Wells, Tilgate, Danny, Charlton, near 

 Brighton, and Buckhurst Park, Sussex ; near Penshurst, Kent ; Shiere, 

 Surrey ; Little Waltham, Pod's Wood, Messing and Epping Forest, 

 Essex ; Craigforda, Shropshire ; near Malvern, Worcestershire ; near 

 Dolgelly and Yns-faig, near Barmouth, Merioneth ; Castle Bernard 

 Park, Bandon, Riverstown and Rostellan, Cork ; Killarney, Kerry. 



Form obtusa A. L. Sm. — Apothecia rounded and obtuse at 

 the ends, frequently furcate or sparingly branched, almost 

 superficial, the thalloidal margin almost disappearing. — Hymeno- 

 decton dendriticum var. ohtusa Leight. torn. cit. p. 388. Graphis 

 dendritica f. obiusa Leight. Lich. Fl. p. 368 ; ed. 3, p. 431. 



A distinctive form owing to the rather crowded and short blunt 

 superficial lirellae. Leighton notes branching at an obtuse angle as 

 characteristic, but the branches form quite as frequently a right angle 

 with the main apothecium. 



Hah. On trees. — Distr. Rather rare, but coextensive with the 

 species. — B. M. Torquay and near Ilsington, Devon ; Kemble, Wilts ; 

 Castle Bernard, Cork ; Cromaglown, Killarney, Kerry. 



3. Ph. Lyellii A. Zahlbr. in Engler & Prantl Pflanzenf. i. 1*, 

 p. 99 (1905). — Thallus thin, membranaceous, smooth, pale-olive 

 or rather dark (K + yellowish). Apothecia brownish-black, 

 sessile, oblong or linear-oblong, straight or curved, simple or 

 sparingly branched ; proper margins thin, the thallus forming a 

 prominent white pulverulent border ; disc broad, plane, pruinose ; 

 hypothecium dark and carbonaceous ; paraphyses inspersed with 

 small granules, slightly swollen and dark at the tips, somewhat 

 conglutinate ; spores elongate-linear, 5-7-septate, brownish, 

 becoming dark, 0,017-33 mm. long, 0,006-8 mm. thick. — 

 Opegrapha Lyellii Sm. Engl. Bot. t. 1876 (1808) ; Hook, in Sm. 

 Engl. Fl. V. p. 147. Graphis Lyellii Ach. Syn. pi. 85 (1814); 

 S. F. Grav Nat. Arr. i. p. 503 ; Mudd Man. p. 241 ; Cromb. 

 Lich. Brit. p. 97 ; Leight. Lich. Fl. p. 369 ; ed. 3, p. 432. 

 Chiographa Lyellii Leight. in Ann. Mag. Nat. Hist. ser. 2, xiii. 

 p. 388, t. 7, f. 24(1854). 



Exsicc. Carroll Lich. Hib. n. 12; Cromb. n. 194. 



Distinguished from the preceding species by the well-developed 

 carbonaceous base of the apothecia. 



