— 139 — 



4. Arthonia (Ach.) Wain. 



71. A. (subg. Arthotheliiim) Riiana Mass., Ric. Aut. Lich. Crost. 

 (1852), p. 49; Willey, Syn. Arth. (1890), p. 52. A. Ruana Anzi, Lich. 

 Exs. It. Sup. (1865), no. 383 (no. 5660 in herb. Nyl.). Dermatina 

 Ruana Almqu., Mon. Arth. Scand. (1880), p. 8. 



Thallus tenuis, laevigatus, albidus, continuus, epiphloeodes. Apo- 

 thecia rotundata aut difformia confluentiave, aggregata aut approximata, 

 long. 0,2 — 1 mm., latit. 0,2 — 0,5 mm., disco piano aut depresso-convexo, 

 thallum aequante aut leviter superante, primum fragmentis thallinis sparsis 

 obducta, dein nuda nigraque. Hypothecium albidum vel pallidum. Hy- 

 menium jodo intense persistenter caerulescens, ascis dilute violascentibus. 

 Epithecium fusco-fuligineum. Asci obovoidei, parte superiore pachyderma- 

 tici, long. circ. 0,060 mm., crass, circ. 0,030 mm. Sporae 8 : nae, deco- 

 lores, ellipsoideae aut oblongae aut ovoideae, murales, seriebus cellularum 

 transversalibus 10—9, jodo leviter vinose rubentes, halone nullo indutae, 

 apicibus rotundatis aut altero apice rolundato-obtuso, long. 0,020 — 0,023, 

 crass. 0,009—0,010 mm. 



Ad corticem Rhizophorae prope Stationem navalem Lem Ngob 

 (no. XIV). 



Ab hac A. anastomosans (Ach.) Nyl., Lich. Scand., p. 259 (Willey, 

 Syn. Arth., p. 53), secund. no. 5640 in herb. Nyl. thallo hypophloeode 

 et „gelatina hymeniali jodo vinose rubente" distinguitur. Etiam in speci- 

 mine Anziano A. Riianae (Anzi, 1. c. no. 383) hymenium jodo caerule- 

 scens. A. ahnormis (Ach.) Nyl., Syn. Lich. Nov. Gal., p. 64, Willey, 

 Syn. Arth., p. 53 (Miill. Arg., Graph. Feean., p. 60), habitu huic con- 

 gruens, observante Nyl. reactione jodetica ab ea differt (no. 5746 in hb. Nyl.). 



Var. phaeospora Wain. 



Sporae dernum fuscescentes , long. 0,020 — 0,024, crass. 0,008 — 

 0,012 mm., murales, jodo leviter vinose rnbentes. Hymenium jodo 

 caerulescens. Hypothecium albidum vel pallidum. 



Ad corticem Arecae prope Stationem navalem in insula Koh Ghang 

 (no. X). 



Area: A. Ruana in Europa et Asia crescit. 



72. A. (subg. Euarthonia) complanata Fee, Ess. Grypt. Ecorc. (1824), 

 p. 54; Wain., Elud. Lich. Bres. II (1890), p. 154; Willey, Syn. Arth. 

 (1890), p. 40. 



Thallus albidus, opacus, continuus. Apothecia anguloso-rotundata 

 aut difformia, long. 1 ,2 — 0,3 mm., latit. 0,7 — 0,3 mm., crass, circ. 0,080 mm., 

 disco nigro, epruinoso, opaco, piano. Hypothecium pallidum. Hymenium 

 et hypothecium jodo persistenter caerulescentia. Epithecium fuscescens 

 aut olivaceo-fuscescens. Asci subglobosi aut pyriformi-subglobosi, long. 

 0,035, crass. 0,030 mm. Sporae 8 : nae, decolores, 5-septatae, cellula 

 apicis crassioris cellulis medianis triplo longiore, etiam cellula apicis 

 tenuioris medianis longiore, long. 0,023—0,025, crass. 0,007—0,008 mm. 



