276 Rev. W. A. Leighton on the British Umbilicarisc. 



from the umbilicate thallus; but Acharius, in bis Meth. Lich. 

 1803, changed it to Gyrophora from the external appeavanee of 

 the fructification, because he thought it most probable that 

 future observation would show that Lecidea Oederi, silacea, pri- 

 vigna, and other species also, ought to be included in the same 

 genus, because their apothecia became deformed or gyriform 

 like those of Umbilicaria, in which case the former name Umbi- 

 licaria would not be applicable to the genus thus compre- 

 hensively considered. Dissection and the microscope have shown 

 that these conjectures of Acharius were groundless, and that 

 there was no real necessity for a change of the generic name. 

 He describes in this work fifteen species, all of which are true 

 Umbilicarics, but refers pustulatus to Lecidea. Ventenat again 

 changes the generic name to Capnia. DeCandolle, in Flor. 

 Fran9. 1805, adopts the genus Umbilicaria of Hofifmann and 

 Acharius, and enumerates tliirteen species, several of which are 

 now considered as varieties or states of the same plants. Acha- 

 rius retains his name Gyrophora in his Lich. Univ. 1810, de- 

 scribing eighteen species, including murinus and pustulatus. 

 Florke has some remarks on the genus in the Berlin Magazine 

 for 1810, but which I have not seen. Wahlenberg (Fl. Lapp. 

 1812) changes the name of the genus to Gyromiurn, but without 

 assigning any reason for so doing, which name he continues 

 in his Flor. Carpath. (1814), Flor. Upsal. (1820), and Flor. 

 Suec. (1824-26). In this latter work he explains the cause of 

 the change to be, from the similarity of the fructification to in- 

 testinal convolutions. Turner and Borrer in the Lichenographia 

 Britannica (1813) retain the name Gyrophora, as air the generic 

 distinctions in that work had been taken from the fructification. 

 They describe ten species as found in Britain, with an elaborate 

 care and minute fidelity and accuracy which cannot be praised 

 too highly. Another valuable feature of this work was the de- 

 termination of the plants of Linnteus and Dillenius from their 

 respective herbaria. Acharius (Syn. 1814) extends the number 

 of species to nineteen ; one of them, G. Clementei, growing on 

 wood, is now referred to Thelephora quercina, Pers., all the rest 

 being saxicolar plants. Scha^rer, in Meisner's Naturw. Anz. 

 1817, has a paper on the Gyrophora, and another on the ^' Umbi- 

 licaria Helvetica '' in Seringe's Musee Helvetique d'Hist. Nat. 

 1821. These he arranges under six species, which he describes 

 at length, adding full synonyms from Vaillant downwards, and 

 illustrates them with five plates filled with beautifully coloured 

 figures of all the species and varieties. In his Spicilegium he 

 refers U. pustulata to Lecidea, and places all the rest under four 

 species, viz. U. depressa, U. polymorpha, U. anea, and U. erosa ; 

 whilst in his Enumeratio (1850) he again includes ;>«*s/m/«/«, and 



