Lecidea. 45 



Subg. IX. Psora (Hall.) Th. Fr. Thallus squamulosus aut 

 squamaeformi-areolatus aut e verruculis demum in isiclia accre- 

 scentibus constans. Apofhecia laetius colorata aut atra. Sporae 

 simplices, decolores, parvae aut minores. 



Psora Hall., Hist. Stirp. Helv. Ill (1798) p. 93 pr. p. Mass., Ric. Lich. 

 Crost. (1852) p. 90 pr. p., Mem. Lich. (1855) p. 123; Koerb., Syst. Germ. (1855) 

 p. 175 (em.); Mull. Arg., Princ. Classif. (1862) p. 40. Lecidea A. Psora Th. 

 Fr., Lich. Scand. (1874) p. 411. 



47. L. breviUSCUla Nyl., Lich. Nov.-Gran. ed. 2 (1863) p. 

 339, Lich. Nov.-Gran. Addit. (1867) p. 321 (mus. Paris.). Psora 

 hreviuscula Mull. Arg., Lich. Beitr. (El. 1882) p. 494. 



Thallus squamulosus, aut fere foliaceus, squamis incisis la- 

 ciniatisve, laciniis crenulatis et insico-crenulatis aut demum mar- 

 gine fere isidioso-laceratis, partim sublinearibus, circ. 0,5 — 0,3 

 millim. latis, cire. 5—1 millim. longis, aclnatis, demum plus mi- 

 nusve imbricatis, planis aut convexiusculis, stramineo-glaucescen- 

 tibus aut stramineo- vel olivaceo-pallescentibus, inferne et ad 

 ambitum hypothallo vulgo bene evoluto byssomorpho fusco aut 

 pallido instructus. Apothecia circ. 0,8—2. millim. lata, testaceo- 

 fuscescentia, aut pallida, convexa aut planiuscula, immarginata 

 aut margine demum evanescente exclusoque. Hypothecium fulve- 

 scens aut testaceo-pallidum, KHO non reagens. Sporae 8:nae, 

 oblongae aut fusiformi-oblongae aut ellipsoideae, long. 0,0 5— 

 0,oio, crass. 0,ooi5— 0,002 millim. [—0,0 045 millim., observante 

 Nyl, Lich. Nov.-Gran. p. 339 1. 



Ad corticem arborum pluribus locis prope Lafayette et Sitio 

 (1000 metr. s. m.) in civ. Minarum, n. 337, 338, 795. — Valde est 

 variabilis et verisimiliter in L. parvifoliam Pers. (Nyl., Lich. 

 Nov.-Gran. ed. 2 p. 339) transit. — Thallus superne strato cor- 

 ticali instructus, 0,o 5 o— 0,0 3 millim. crasso, pellucido, decolorato, 

 chondroideo, ex hyphis format o subverticalibus, ramosis, conglu- 

 tinatis, membranis incrassatis, lumine cellularum angusto, oblongo 

 aut fere parenchymatico. Infra zonam gonidialem adest stratum 

 medullare tenue tenuissimumve, hyphis intricatis, sat leptoderma- 

 ticis, in hyphas hypothallinas continuatis. Hypothallus ex hyphis 

 circ. 0,0 4 millim. crassis, maxima parte fasciculatis et fere rhi- 

 zinas formantibus, at parum conglutinatis, membranis sat tenui- 

 bus, lumine sat lato, cellulis elongatis. Gonidia globosa, diam. 



