LICHENES — DR JEAN MTJLLER. 385 



12. CHIODECTON. 



CModecton, Ach. Syn. p. 212; Nyl. Essai 190; Stitzb. Beitr. 152. 



A small genus of nice habitus ; the species are generally tropical, but three 

 are found in the western and southern Europe. 



1. C. nanum, Mull. Arg. in Proc. Koy. Soc. Edin. xi. (1882), 470. 



Thallus albus, crassiusculus, sequalis et laevigatus, determinatus, non linea aut zona hypothallina 

 cinctus, demum tenuissiioe rimulosus ; verrucse fructigerse vix emergentes, levissime con- 

 vexae et thallo leviter albiores, irregulariter oblongse ; apothecia irregular! ter subseriatini 

 disposita, immersa, extus punctulis depressis fuinoso-nigricantibus tantum ^-^ mm. 

 • latis distincta, pro parte gregatim approxiraata aut astroideo-confluentia, tota in sectione 

 verticali fere \ mm. lata, basi profunde convexo-arjgustata et undique cum marginibus tectis 

 completis sed valde tenuibus (j^—ifa mm. crassis) nigra; sporae in ascis subangustis 

 octonse, hyalinae, fusiformes, 21-24 fx longae, 5 fx latae, 5-7-septatae, loculi aequales. 



Affine Ck. effuso F^e sed verruca? nanissimae, multo minores, apotbecia conferta et minora et 

 sporae 6-8-loculares. 



Soeotra. In ramis Dracaenas cum Graphina nariante et Opegraplm 

 Draccenarum, supra Wadi Kischen, alt. 700 m. Schweinf. 

 Distrib. Endemic. 



2. O. circumscissum, Mull. Arg. Proc. Koy. Soc. Edin. xi. (1882), 470. 



Thallus argillaceo-cinereus, lineis nigris crebre decussatus, tenuis, obsolete v. demum distincte 

 verrucigerus, superficie leevis ; gonidia cbroolepoidea ; apothecia in verrucis convexis 

 mediocribus subirregularibus conferta, orbicularia v. oblongata, depressa, prim urn caesio-v. 

 albido-pruinosa, mox nudata et nigra, £-£ mm. lata, semper distincte depressa et a thallo 

 nonnihil arrecto circumscisso-libera, subinde pro parte astroideo-confluentia et Artlwniam 

 simulantia ; perithecium lateraliter tenue, basi autem profunde conice in thallum 

 descendens, atro-fuscum, epithecium fuscum ; lamina hyalina ; asci 8-spori ; sporae 

 hyalinae, circ. 36 li longae, 5 fx latae, more Platygrapharum 9-12-loculares. 



Prope CModecton Kurzei, Nyl. Lich. Andam. p, 13 locanda videtur. 



Soeotra. Corticola ad ramulos minores. B.C.S. n. 1319. 

 Distrib. Endemic. 



3. C. socotranum, Midi. Arg. in Proc. Eoy. Soc. Edin. xi. (1882), 470. 



Thallus fere 1 mm. crassus, tartareus, albus, primum continuus v. obsolete rimulosus, dein 

 areolato-rimosus, farinulentus, hinc inde linea fusca v. nigra hypothallina cinctus ; verrucae 

 fertiles albo-virentes et thallo keviores, 1-5-carpicae, irregulariter depresso-hemisphaericae, 

 rnodice tantum ernersse et basi baud contractae ; ostiola punctiformia, nigra, subastroideo- 

 confluentia, haud peculiariter marginulata ; epithecium fuscum ; lamina hyalina ; hypo- 

 TRANS. ROY. SOC. EDIN. VOL. XXXI. 3 C 



