LICHENES. 2&g 



ventralis, hoc est in utraque facie dissimilis elementaque constitutiva in superpositis stratis 

 disposita praebens. Cortex superior plerumque plectencliymaticiis; in eo hjphae superficiei 

 perpendiculares, vel in Coccocarpise sectionis speciebiis parallelae, arcte coalitœ, repetito 

 septatae cellulasqiie parvas magnasve formantes; in diiplice specie hyphae decomposita', 

 arcte coadunatœ, constricte septatae, lateraliter ramosœ ramis anastomosantibus reteque 

 effîcientibus ; supra cellulas corticis et prœsertim in sect. Psoromate zona crassa et fere 

 amorpha sœpe conspicua. Gonidia in sect. Psoromate viridia et vulgo protococcoidea, in 

 unica specie pahnellacea ; in sect. Eupaniiavia et Coccocarpia, cyanophycea et 

 nostococacea aut scytonemea stratumque sub cortice formantia ; inter ea hyphœ goni- 

 diales septatae et plus minusve la\e coadunatœ. Hyphae mediillares saepe nudae, interdum 

 materia subalbida aut atrata nubilatœ, superficiei parallelae, vel ramosœ et plus minusve 

 laxe coalitœ in sect. Psoromate et Eupannaria, vel strictijssime conglutinatœ in 

 sect. Coccocarpia. In paucis sect. EupannarUe speciebus, duplex medullare stratuin, unum 

 sub cortice et ante gonidia, alterum in loco solito, sub strato gonidiale. Cortex inferior 

 in unica sect. Psoromatis specie existens et in cœteris defîciens. Pagina infera raro albida, 

 sœpius fusca, nigra aut cœrulescens, acsubstrato vel rhizinis fulcrantibus, vel hyphis hypo- 

 thallinis aut simplicibus, aut fibrillas formantibiis et in strato plus minusve crasso coadunatis 

 adhœrentes; interdum illœ hyphœ accrescentes pannum etiam extra thalli peripheriam protusum 

 efficientes. Apolliecia supra thallum dispersa vel conferta, aliquando marginalia, sessilia, 

 in basiconstricta, cupuliformia aut demum in paucis sect. Coccocarpise speciebus adnata 

 planaque, duplice integumento vestita atque margine parum vel non aut e contra multum 

 elevato, integro seu crenato atque disco sœpe rufo, passim fusco, nigrescente vel carneo 

 instructa. Excipulum nunc thallo concolor, nunc aliter coloratum et ejus cortex plerumque 

 plectenchymaticus. Perithecium in unica specie, n. 472, coloratum ; in eo hyphœ nunc simpli- 

 citer septatœ, nunc contextum plectenchymaticum formantes. Gonidia hyphœque medullares 

 inter utrumque inlegumentum nunc vigentia, nunc deficientia. Paraphyses hyalinœ et 

 articulatœ. Sporœ octonœ, hyalinœ, simplices et in unica specie, n. 453, polariloculares, 

 oblongœ vel ellipsoideœ, rarius sphœricœ vel fusiformes, in sect. Eupannaria in ambitu ali- 

 quando serratulœ ac in uno vel in utroque apice breviter apiculatœ, exosporio interdum 

 incrassato atque in sect. Psoromate aliœ aliis verticaliter adhœrentes. Spcrmog'onia 

 supra thallum et prœcipue in ejus peripheria enata, verrucosa et parum prominentia, 

 extus nigra aut fusca et intus cortice plectenchymatico circumdata albidaque. Spermatia 

 parva, recta, vel omnino cylindrica vel in utroque apice incrassatula. Sterigmata articu- 

 lata articulis parvis, ramosa ac demum alla aliis adhœrentia; in sola P. triptophylla, 

 teste cl. Lindsay, non articulata. Ccphalodia in sola sect. Psoromate observata, nunc 

 epigena, thallo paulum discoloria, globosa seu applanata lobulataque et nunc endogena. 



Sectio I. — PsoROMA Tuck. 

 Synops. Nortli Americ. Lich.^ I, 1882, p. 117 ; genus Psoroma Nyl. supra indicatum. 



§ I. — Sporae simplices. 



A. — ThALLUS DCPLICE CORTICE OKNATUS. 



441. Pannaria Hypnorum Kœrb. Syst.Lich. German.{i%oo'] p. 108, Schwend., Unter- 

 sucli. Flechtenth., 1862, p. 69, tab.XI, fig. 7, Tuck. Gêner. Lich. p. 48, et Synops. North 

 Americ. Lich.,1, p. 117, atqueGliick, EntwurfFlecht .-Spermoy., p. 80; Lichen Hypnorum 

 Hornemann et Wahlenberg, in OeAer Flora danica, t. VI, 1787, tab. 956, Sowerby, Eîiyl. 



