Rev. Vf . A. Leighton on the British Umbilicarise. 277 



rearranges the various forms into eight species. British authois, 

 as Piirton, Midi. V\. (1817), Hooker, Fl. Scot. (1821), and 

 Greville, Fl. Edin. (1824), adopt Gijrophora as the genus. Fries 

 in all his works resolutely maintains the original name, Unibili- 

 carin, of Iloffinaun. Esehwciler, Syst. Lich. 1824, places Gyro- 

 phora in e()m|)a:^y with Solorhin, Ach., Dermntocarpon, Esehw., 

 Endocarpon, Hedw., Copitiilaria, Eschw,, and Peltidea, Ach., in 

 his Cohors V. Dermatucarpece. Wallroth, Crypt. Germ. (1831), 

 makes Un.bilicuria a section of his genus Graphis, considering 

 tlic affinity in structure of the apothecia with those of the Gra- 

 phide<e, hinted at by Bernhavdi, Florke and DcCandollc, to be cor- 

 rect and well founded. Hooker in ]3rit. Flor. (1833) follows the 

 arrangement of Fee (Cryptog. Ecorccs, 1824) into Gyrophora and 

 Uinhilicana, from the different external aspect of the apothecia. 

 His distribution of the species differs somewhat from that of the 

 ' Lichenograj)hia Britannica.^ Dr. Taylor in Flora Hibernica 

 (1836) again unites the two genera. Merat in Flor. env. Paris 

 (1830) ])uts U. pus/u/a/a into a new genus called Lasallia. Che- 

 vallier (Flor. l^aris, 1836) and Flotow (Lichenes Flor. Siles.,1850) 

 separate Umbilicaria and Gyruphora. Tuckerman, Syn. Lich. 

 Amer. (1848), retains the entire genus Umbilicariu, HotTm., with 

 a moditied generic character. 



Massalongo (Licheni Crostosi, 1852) retains Umbilicaria, 

 Hoffm., for the generality of the s})ecies, but refers U. pustulata 

 to a new genus, Macrodictya, his distinctions being taken from 

 the dissimilarity of the sporidia. In his jNlemorie Lichenog. 

 (1853) he rejects his new genus Macrodictya and ado])ts Merat's 

 Lasallia. In his Systema Lichenum Germanic (1854) Koerber 

 sej)arates Umbilicaria {pustulata) from Gyrophora . Nylander in 

 his " Nouvelle Classification des Lichens " in I\Iem. Soc. des Sc. 

 \at. de Cherbourg (1854 & 1855), retains the original and com- 

 prehensive genus of Hoffuiann, Umbilicaria, as the type of his 

 tribe GyrophureaE. 



From the preceding summary it is seen, that whilst the plants 

 have retained their relative position as members of a closely con- 

 nected group, considerable difference of opinion has existed as 

 to the name which should be assigned to it, and whether Umbi- 

 licaria pustulata should be included in the same genus, or form 

 a distinct genus by itself. From the identity of structure both 

 of thallus and aj)othecium, I incline to think that it ought, with 

 the other ])lants, to constitute one and the sanie genus, and that 

 the original name of Hoffmann, Umbilicaria, which appears to 

 have been changed from no really substantial scientific reasons, 

 should be restored to it. 



The learned authors of the * Lichenographia Britannica ' com- 

 plain, and with justice, that the genus has been divided into too 



