GEAPHIDACEAE. 535 



6. Opegrapha isabellina Riddle, sp. now 



Thallus crustaceus uniformis effusus haud limitatus, isabellinus minute 

 albo-maculatus, tenuis continuus laevigatus. Gonidia chroolepoidea. Apotheeia 

 dispersa aut rarius aggregata superficialia elevata, simplicia recta aut rarius 

 flexuosa, oblonga aut linearia, 0.8-2.0 mm. longa, 0.1-0.2 mm. lata, tota nigra, 

 labiis haud suleatis conniventibus disco rimaeformi; amphithecio nigricante 

 integro basi complete Paraphyses ramosae. Asci clavati, 8-spori. Sporae 

 incolores, fusiformes, 6-8-loeulares loculis cylindricis aequalibus, 20-24 X 4-5 p.. 



On limestone, New Providence (Brace, May 20, 1918, 9$37, type). In the Tucker- 

 man Herbarium there is an unnamed specimen of this species from Cuba, sent to 

 Tuckerman by Ravenel. 



Scarcely anything is known of the rock-inhabiting Opegraphas of the tropics. I 

 have been unable to find any described in the writings of Nylander, Mueller-Argau, 

 or Wainio. The three new species here described appear to be distinct from the 

 European species. 



7. Opegrapha bahamensis Riddle, sp. nov. 



Thallus crustaceus uniformis effusus haud limitatus, testaceus, sat cras- 

 siusculus laevigatus aut rugulosus, rimulosus partim areolatus, sorediis nullis; 

 hypothallo nullo. Gonidia chroolepoidea. Apotheeia dispersa aut rarius aggre- 

 gata, primum subinnata mox superficialia elevataque, simplicia recta, pro 

 maxima parte brevia oblonga, 0.4-0.7 mm. longa, rarius subelongata, ad 1.5 

 mm. longa, 0.1-0.2 mm. lata, tota nigra, labiis haud suleatis conniventibus aut 

 rarius hiantibus, disco rimaeformi aut rarius paullum aperto; amphithecio 

 fusco-nigricante integro basi complete Paraphyses sparse ramosae. Asci 

 clavati, 8-spori. Sporae incolores fusiformes, 6-loculares loculi cylindricis 

 aequalibus, 18-20 X 3-4 /x. 



On limestone, New Providence (Brace, June 5, 1918, 9!i5ba, type). 



Opegrapha bahamensis resembles O. Chevallieri var. incarnata Riddle (Bull. 

 Torrey Bot. Club 43 : 150. 1916), but differs in the six-celled spores. From O. zonata 

 Koerb., it differs in the absence of soredia and hypothallus. The key-characters will 

 serve to distinguish it from O. isabellina. 



8. Opegrapha columbina Riddle, sp. nov. 



Thallus crustaceus uniformis effusus haud limitatus, columbina aut 

 plumbeus aut partim nigrescens, tenuissimus farinulentus. Gonidia chroole- 

 poidea. Apotheeia dispersa aut conglomerato-approximata, superficialia ele- 

 vata, simplicia recta oblonga, 0.5-1.5 mm. longa, circa 0.2 mm. lata, tota nigra, 

 labiis haud suleatis conniventibus disco rimaeformi; amphithecio nigricante 

 integro basi eompleto crasso. Paraphyses ramosae. Asci clavati, 8-spori. 

 Sporae incolores fusiformes, 8-loeulares loculis cylindricis aequalibus, 24-2S 

 X 5-7 ft. 



On limestone, vicinitv of Governor's Harbor, Eleuthera Island (Britton and 

 Millspaugh, February 19-20, 1907, 5533, type). 



This species is most closely related to Opegrapha ophites Tuck, fapud Riddle in 

 Bull. Torrey Bot. Club 43: 150. 191G), but differs in the short, straight, oblong 

 apotheeia. From O. lithyrga Ach. it may be distinguished by the color of the thallus 

 and the wider spores. 



2. GRAPHIS Adans. 



Apotheeia externally black. 



Apotheeia 0.4-1.0 mm. in length. 1. G. Paroniana. 



Apotheeia mostly 2-5 mm. in length. 2. G. scripta. 



Apotheeia not externally black. 



Apotheeia white, contrasting with the dark thallus or bark. 3. G. Afzelii. 

 Apotheeia concolorous with the glaucous thallus. 



Lips entire or nearly so. 4. <:. veattta. 



Lips deeply silicate. 5. G. cinerea. 



1. Graphis Pavoniana Fee, Essai Crypt. 40. 1S24. 

 On bark, New Providence : Texas ; Bermuda. 



