84 Rev. W. A. Leightou on the British Graphidese. 



works retains all under Opegi'apha and Arthonia. Fee in the 

 first part of his *^Essai sur les Cryptogames ' (1824) divides the 

 Chmphidece as follows -. — ^^ Arthonia y fausses lirelles sessiles, ho- 

 mogenes, immarginees, non impressionees " r=z Arthonia, Ach. 

 L. Univ. " Heterographa, fausses lirelles sessiles, homogenes, 

 maculiformes en vieillissant^ pourvues d^mie fente dans la 

 jeunesse/' founded on Opeyrapha faginea and quercina, DC. 

 {Opeg, macularis, Ach.), which is regarded by Fries as a fungus, 

 and perhaps justly. *' ^?zifero^rflp/i«, lirelles profondement im- 

 mergees, homogenes, non impressionees/' founded on Opegrapha 

 crassa, DC. [Sagedia aggregata, Fries). " Opegrapha, lirelles 

 sessiles, homogenes, impressionees " = Opegrapha, Ach. L. Univ. 

 '^ Graphis, lirelles sessiles, heterogenes, canaliculees '' = Graphis^ 

 Ach. L. Univ. '^ Sarcographa, lirelles labyrinthiformes k base 

 charnue.^^ *' Fissurina, fausses lirelles situees inferieurement, 

 determinant une fissure dans le thallus qui margine.^' 



Eschweiler (Syst. Lich. 1824) makes nine genera out of Ope- 

 grapha, Graphis and Arthonia of Acharius, using the form and 

 structure of the hrella as the foundation of his arrangement ; viz. 



1. Diorygma, type Opeg. hieroglyphica, Pers. Act. Soc. Wetter. 



2. 16. t. 10. f. 3, ''^orbis novi incolse." 2. Leiorreuma, which 

 includes many tropical species of Graphis, Ach. As its type 

 Opegrapha Lyellii, Eng. Bot. t. 1876. is given, but the section of 

 that plant which is represented with an entire perithecium sur- 

 rounding the base, as is really the case in the authentic spe- 

 cimens which I have examined in herb. Borrer., does not corre- 

 spond with the section of the same part in the figure of Leior- 

 reuma hepaticum given by Eschweiler, in which the perithecium 

 is lateral only in accordance with the generic description. 



3. Graphis = Graphis, Ach., according to the figures given, and 

 those of Acharius, ' Lich. Univ. ' (t. 3. figs. 14, 15) referred to. 



4. Opegrapha = Opegrapha, Ach., section 1. Hysterina, Ach. 



5. Oxystoma, type Op. cyUndrica,llsidd. Act. Soc. Ital. della Sci- 

 enza, xviii. 1820, tome iii. fig.l. 6. Scaphis= Opegrapha, Ach., 

 section 2. Alyxoria, Ach. 7. Lecanactis, type Arthonia lyncea, 

 A.ch. 8. Sclerophyton, Eschw., " perithecio mere infero, nucleum 

 tenuem sufFulcientc, disco planiusculo.^'' 9. Pyrochroa, types 

 Graphis coccinea, Holl. ; G. caribcea, Ach. — all tropical plants. 

 Eschweiler figures the sporidia of each genus, but in Fee's esti- 

 mation incorrectly. Fries in his ' Systema Orbis Vegetabilis ^ 

 (1825) re-arranges them in six genera: — 1. Graphis = Leiorreuma, 

 Eschw. ; its type Graphis Afzelii, Ach. 2. Opegrapha in four 

 subgenera, viz. A. Hysterina— Opegrapha, Eschw., and Opegrapha 

 sect. Hysterina, Ach. B. Oxystoma, Eschw. C. Scaphis, Eschw., 

 and Opegrapha, sect. Alyxoria, Ach. D. Erumpentes= Graphis, 

 Eschw. [and by consequence Graphis, Ach.]. 3. Lecanactis, 



