PYKENULACEAE. 



523 



3. Verrucaria muralis Ach. Meth. Lich. 115. 1803. 



On limestone, New Providence ; — cosmopolitan. 



4. Verrucaria nigr^scens Pers. in XJsteri, Ann. Bot. 14: 36. 1795. 



On limestone, New Providence : — ^North America and Europe. 



Family 2. PYRENULACBAE. 



Spores plurilocular (two to many-celled). 

 Spores colorless. 



Spores with cylindrical cells. 



Paraphyses simple and persistent. 

 Paraphyses branched or deliquescent. 

 Spores with lens-shaped or rounded cells. 

 Spores brown. 



Paraphyses simple and persistent. 

 Paraphyses branched or deliquescent. 

 Spores mnrlform-multilocular. 

 Spores colorless. 



Paraphyses simple and persistent. 

 Paraphyses branched or deliquescent. 

 Spores brown. 



1. POKINA Ach. 



Peritheclal wall entirely black. 



Thallus chalky-white ; perithecia 0.6-0.8 mm. in diameter. 

 Thallus greenish or purplish ; perithecia 1.0-1.5 mm. in di- 

 ameter. 

 Perithecial wall black at the tip only, or not at all. 

 Tballus subfoliose, on rocks. 



Thallus with loosely adherent, convex lobes. 

 Thallus closely adnate, flat and merely crenate. 

 Thallus crustose, on bark. 

 Ostiole brown or reddish. 

 Ostiole blackening. 

 Spores 7-15 » wide. 

 Spores 4— 6u wide. 



Thallus marked with frequent black lines. 

 Thallus without such lines. 



1. Porina WUsonii Riddle, sp. nov. 



Thallus epilithieus crustaceus uniformis effusns hand limitatus, eretaceo- 

 albus opacus tartareus, crassiusculus continuus laevigatus, spermagoniis eopiose 

 nlgropunctatus. Gonidia chroolepoidea. Perithecia globosa Integra nigra, 

 0.&-0.8 mm. lata, primum tota immersa maculis nigreseentihus indicata dein 

 semiemergentia, alte eonvexa, strato tenue thallode fere ad instar prninae 

 velata, demura apicibus denudatis, ostiolis minutis umbonatis, nunquam elabentia. 

 Paraphyses persistentes tenues simplices. Asci cylindrioes 8-spori. Sporae in 

 ascis uniseriales, incolores f usif ormes 4-loculares loeulis cylindricis, 13-15 X 4^5 /t. 

 Spermagonia minuta nigra apicibus emergentibus denudatis. Spermatia recta 

 bacillaria, 3-^5 X 1/t. 



On limestone, Caleta Cocodrilos, Isle of Pines, Cuba (Britton, 'Wilson, and Le6n, 

 March 8, 1916, ISSSS, type). 



Bahamas : on limestone. New Providence (Brace, 9SSi) ; Governor's Harbor, 

 Eleuthera (Britton and Millspangh, 55S5). A lichen occurring near the Columbus 

 Monument, Watling's Island, and showing spermagonia only, agrees with this species, 

 but the determination can not be considered certain. 



This species, which I take pleasure in naming in honor of Mr. Percy Wilson, 

 may be distinguished from other species of the section Sagedia, to which it belongs, 

 by the chalky-white, tartareous thallus, and the delicately pruinose perithecia. It 

 bears a strong external resemblance to Verrucaria mamillaris, but can, of course, 

 be at once distinguished by the spores. 



2. Porina macrocarpa Riddle, sp. nov. 



Thallus epilithieus crustaeeus uniformis effusus linea nigra limitatus, 

 glaucus virescens aut purpurascens opacus, crassitudine mediooris aut tenuis. 



1. PorUia. 



2. Arthopyrenia. 



3. Pseudopyrenula. 



4. Pyrenula. 



5. Microthelia. 



6. Olathroporlna. 



7. PolyTilastiopsis. 



8. AntJiracothecium. 



1. P. 'WUsonii. 



2. P. macrocarpa. 



3. P. flrmula. 



4. P. suifirmula. 



5. P. nucula. 



6. P. mastoldea. 



7. P. variegata. 



8. P. Tetracerae. 



