86 Rev. W. A. Leighton on the British Graphidese. 



Fries, S. O. V.; with the characteristics, "Apothecium immer- 

 sum, perithecio infra deficiente, discum canaliculatum elevato- 

 marginante." II. Opegrapha = Ojiegrapha, Ach. ; Opegrapha 

 and Scaphis, Eschw. Syst. ; Opegrapha hysterina and Scaphis, 

 Fries, S. O. V.; Opegrapha hystei'ina and Allograp ha species, 

 Chev., with the distinctions, " Apothecium emersum, perithecio 

 integro, discum plano-canaUculatum suffulciente/' 3, Oxystoma 

 = Oxystoma, Eschw. Syst., and Opegrapha Oxijstoyna, Fries, 

 S. O. v., with an entire perithecium converging upwards. 4. 

 Leiogramma, with, as it appears to me, somewhat of an inde- 

 finite character, the base of the perithecium being described as 

 either entire or deficient, and yet he remarks, '' perithecium 

 Hcet subinde tenuissimum, in perfectis adultis nunquam deest." 

 Hence he concludes that Meyer's characters of his genera Leu- 

 cogramma and Platygramme are erroneous, the former being, in 

 his estimation, a younger, the latter an adult state of the same 

 species of Ustalia, Eschw. It is further remarked, that Leio- 

 gramma " a Graphide strictissime distinguitur defectu marginis 

 proprii ob perithecium omnino latens," and that the nucleus 

 is tetraquetrous. This genus is divided into three sections : 

 I. Leiorreuma, '' perithecio basi deficiente " = Leiori'euma, Eschw. 

 Syst. & Icon. Sel. Crypt, t. 6. f. 2, 3 ; Qraphis, Fries, S. O. V. ; 

 species of Graphis and Atihonia, Ach. & Fee ; species of Leuco- 

 gramma, and perhaps also of Platygramme, Meyer. Opegrapha 

 dendritica, E. Bot. 1756, is cited as being referable here, but 

 this plant has constantly a distinct though very thin perithecium 

 subtending the base, and therefore would seem rather to belong 

 to section 2. II. Lecanactis, " perithecio dimidiato infra sub- 

 continuo " = Lecanactis, Eschw. Syst. & Icon. Sel. Crypt., and 

 Fries, S. 0. V. ; and species of Arthonia, Ach. & Fee. The type 

 of course is, Lecanactis lyncea. III. Medusula = Medusula, l^schw. 

 Syst. & Fries, S. O. V. ; species of Sarcographa, Fee; species of 

 Asterisca, Meyer. 5. Sclerophyton = Sclerophyton, ^schw. Syst., 

 and Fries, S. O. V. 6. Ustalia = Ustalia, Fries, S. 0. V., and 

 Eschw. Icon. Sel. Crypt. ; Pyrochroa, Eschw. Syst. ; species of 

 Platygramme and Leucogramma, Meyer. 7. Arthonia= Arthonia, 

 Eschw. Syst. & Icon. Sel. Crypt. ; species of Arthonia, Ach. 

 L. Univ. 



Borrer in Hooker's 'British Flora,' 2. (1833) arranges in the 

 family Graphidea : 1. Arthonia = Arthonia, Ach., and 2. Ope- 

 grapha= Opegrapha and Graphis, Ach., and Platygramme, Meyer. 

 He sanctions Meyer's genus Platygramme as distinct, remarking 

 that three of our British species, dendritica, Lyellii and venosa, 

 belong to it. 



Taylor in Mackay's 'Flora Hibernica,' part 2 (1836), follows 

 the same arrangement. 



Fee in the 2nd part of his 'Essai' published in 1837 states, 



