206 GRAPHIDEI [aRTHONIA 



83. ARTHONIA Ach. in Schrad. Neu. Journ. Bot. i. 3, 

 p. 3 (1806) emend. & Lich. Univ. p. 25 (1810). (PI. 20.) 



Thallus crustaceous, thin or evanescent, sometimes developed 

 under the bark (hypophloeodal). Algal cells Trentepohlia or 

 Palmellacese. Apothecia innate, sessile, immarginate, roundish 

 (ardellse) or elongate (lirellse), plane or tumid ; asci pyriform 

 or almost globose, rarely elliptical, thickened at the apices ; 

 spores elongate-ovate or clavate, 1- or pluri-septate, colourless 

 or sometimes brownish. 



Includes a number of species that have been formerly classified 

 under different genera, according to the form of the thallus or spores ; 

 they are grouped in three sections : — 



Thallus with Trentepohlia gonidia. 

 Apothecia more or less brightly 



coloured or brown § i. Coniocakpon (1-6). 



Apothecia blackish § ii. Euakthonia (7-20). 



Thallus with Palmella gonidia, or 



wanting § iii. Lecidbopsis (21-28). 



§ i. CoNiocAEPON A. Zahlbr. in Engler & Prantl Nat. 

 Pflanzenf. i. 1*, p. 91 (1903).— Coniocarpon DC. Fl. Fr. ii. 

 p. 323 (1805), pro parte ; Leight. in Ann. Mag. Nat. Hist, 

 ser. 2, xiii. p. 433 (1854). 



Algal cells Trentepohlia. Apothecia brightly coloured or 

 brown, not black ; spores 1- or more-septate. 



Spores l-septate, 



1. A. lurida Ach. Lich. Univ. p. 143 (1810).— Thallus thin, 

 pale-dirty-brown or pale-lead-coloured, smooth, effuse or obsolete. 

 Apothecia {ardellse) reddish or reddish-black, sessile, appressed, 

 irregularly roundish, slightly convex (K-f violet or blue) ; spores 

 broadly ovate, l-septate, colourless or pale-yeUow, 0,010-15 mm. 

 long, 0,004-6 mm. thick ; hymenial gelatine dirty-wine-red with 

 iodme.— Borr. Engl. Bot. Suppl. t. 2692, fig. 2 ; Hook, in Sm. 

 Engl. Fl. V. p. 143 ; Tayl. in Mackay Fl. Hib. ii. p. 104; Leight. 

 in Ann. Mag. Nat. Hist. ser. 2, xiii. p. 442, t. 8, fig. 38 (1854) 

 & Lich. Fl. p. 391 ; ed. 3, p. 414 ; Mudd Man. p. 250; Cromb. 

 Lich. Brit. p. 102 (excl. f. vinosa). 



Exsicc. Mudd n. 236 ; Leight. n. 224 (as A. vinosa). 



Hah. Usually on the trunks of small trees.' — Distr. Frequent in 

 England, somewhat rare in the Channel Islands, W. Scotland and in 

 S. Lreland. — B. M. Withiel, Cornwall ; Balcombe, Blackdown, Hand- 

 cross and Hurstpierpoint, Sussex; near Becky Falls and Newton 

 Bushel, Devon ; New Forest, Hampshire ; Gopsall, Leicestershire ; 

 Bettws-y-coed and Trefriw, Carnarvonshire ; Sutton, near Shrewsbury, 

 Shropshire; Malvern, Worcestershire; Airyholme Wood, Cleveland, 

 Yorkshire ; Windermere, Westmoreland ; Mangerton and Dunkerron, 

 Kerry. 



