524 PYRENULACEAE. 



continuus laevigatus, olim spermagoniis nigropunctatus. Gonidia chroolepoidea. 

 Perithecia 1.0-1.5 mm. lata, solitaria aut confluentia dimidiata, primum im- 

 mersa leviter convexa dein emergentia elevata conico-hemisphaerica, basi innata, 

 nigra sat tenue thallino suffusa aut denudata, apice obtuso aut crasso papil- 

 late, demum elabentia foveolamque relinquentia, amphithecio carbonaceo basi 

 deficient!. Paraphyses persistentes tenues simplices. Asci cylindrices 8-spori. 

 Sporae in aseis uniseriales, incolores ellipsoideae, 4-loculares loculis subcylin- 

 dricis angulis sat rotundatis, 13-16 X 5-7^. Spermagonia mediocria nigra 

 apice emergente denudato. Spermatia filiformia arcuata, 18-22 X I/A. 



On limestone, Key View Hill, Vivijagua, Isle of Pines, Cuba (Britton, Britton 

 and Wilson, February 28-29, 1916, 15090, type). 



Bahamas : on limestone, Cockburn Town, Watling's Island (Britton and Mills- 

 paugh, 6131). 



Known also from two other stations in the Isle of Pines and from one station 

 in Porto Rico. 



The affinities of this snecies seem on the whole to be with the genus Porina, 

 section Sagedia, although it has peculiarities which make its systematic position 

 somewhat uncertain. While the perithecia are for the most part solitary, they 

 occur occasionally completely confluent, except for the papillate tips. Even in these 

 cases, however, there is never any indication of a stroma. The cells of the quadri- 

 locular spores are somewhat more rounded than is typical for Porina. There is no 

 other species with which this is liable to be confused. 



3. Porina firmula Muell. Arg. Bot. Jahrb. 6: 401. 1885. 



On limestone, Andros, at Mastic Point, and Watling's Island, near Cockburn 

 Town : Cuba ; Isle of Pines. 



4. Porina subfirmula Riddle, sp. nov. 



Thallus epilithicus determinatus subfoliosus effiguratus, irregulariter ro- 

 tundatus, margine integro aut crenato baud lobato, planus, arete adnatus, cras- 

 sus (crassitudine 0.15-0.2 mm.), atro-olivaceus, continuus laevigatus vel sat 

 inaequalis nitidulus; snperne corticatus cortice tenue (crassitudine 12-14 /a) 

 pseudo-parenchymatica, inferne ecorticatus. Gonidia chroolepoidea. Perithecia 

 subglobosa circ. 0.3 mm. lata, tota immersa aut apicibus leviter emergentibus 

 et sat denudatis, amphithecio superne nigro inferne decolore. Paraphyses per- 

 sistentes simplices. Asci 8-spori. Sporae incolores fusiformes, haud bene 

 evolutae, 6-8-loculares, loculis cylindricis, circ. 25 X 4/i. 



On limestone, Sierra de las Casas, Isle of Pines, Cuba (Britton and Wilson, 

 March 22, 1916, 157Jfl, type). 



Bahamas: on limestone, New Providence (Brace, 9.)87). 



This species belongs to the section Seycstria, and is evidently related to but 

 quite distinct from the preceding species. Both species are decidedly Endocarpon- 

 like in appearance. 



5. Porina nucula Ach. Syn. Lich. 112. 1814. 



On bark of Exothea, New Providence, at Clifton : widely distributed in trop- 

 ical regions of both hemispheres. 



6. Porina mastoidea (Ach.) Mass. Ric. Lich. Crost. 191. 1852. 



Pyrenula mastoidea Ach. Syn. Lich. 122. 1814. 

 Porina africana Muell. Arg. Linnaea 43: 41. 1880. 



On bark, Great Bahama : widely distributed in tropical regions of both hemi- 

 spheres. 



The material represents a form with verrucose thallus and verruca^, and the 

 latter are somewhat constricted ; but the species is so variable that it is . scarcely 

 worth while to give this form a name. 



7. Porina Tetracerae (Ach.) Muell. Arg. Bot. Jahrb. 6: 401. 1885. 



Verrucaria Tetracerae Ach. Meth. Lich. 121. 1803. 



On bark, New Providence, at Maidenhead Coppice : widely distributed in trop- 

 ical regions of both hemispheres. 



8. Porina variegata Fee, Suppl. Essai Crypt. 75. 1837. 



On bark, Abaco, at Old Kerr's Point : Cuba ; Jamaica ; Porto Rico. 



