28 LINDSAY, ON ABROTHALLUS. 



that the Abrothalli are abortive apothecia of certain familiar 

 foliaceous lichens is maintained so lately as 1850 in Schserer's 

 elaborate ' Enumeratio critica Lichenum Europseorum/ 

 (Berne, 1850). He describes the species mentioned by 

 Hooker as End. parasiticum, under the name of Parmelia 

 saxatilis, \ ox. parasitica, in the following terms : " Tliallo supra 

 apotheciis abortivis, atris, subpatellseformibus vel hemisphse- 

 ricis, immarginatis, consito." His description of the var. 

 abortiva of Parmelia conspersa is precisely similar. Of 

 Parmelia olivacea, var. abortiva, he says, " Thallo supra 

 sphserulis atris (apotheciis abortivis) distincto." These 

 are characteristic descriptions of A. Smithii, the variety 

 which I have hereafter described as o, ater. To my variety 

 pulverulentns of the same species, he refers, sub nom. 

 Sticta fuliginosa, var. abortiva, when he says : " Tliallo supra 

 patellulis superficiaribus, olivaceo-viridi-pulverulentis, immar- 

 ginatis, distincto." Schserer's specific and generic charac- 

 ters have too evidently been founded wholly on external 

 appearances : he himself deplores his deficient microscopical 

 knowledge and skill. But he does not appear to have been 

 aware of — or at least he does not allude to — the researches 

 of De Notaris on the genus Abrothallus, which bear date 

 between the years 184?6 and 1849, — prior to the publication 

 of his own ' Enumeratio.' Of Tulasne's investigations he 

 could not avail himself, as they were published two years sub- 

 sequently. By other observers, again, there has been too 

 great a tendency perhaps to take for granted the bold and 

 sweeping assertion of Fries that " Lichenes in aliis parasitici 

 normaliter nuUi genuini,' — an assertion whose incorrectness 

 the labours of subsequent observers have suflficiently proved. 

 It has been too much the custom lazily and ignorantly to 

 refer minute, black, point-like or spot-like parasitic lichens 

 to the great family of the Fungi; but I feel assured that 

 many species of Sphreria, Dothidea, Peziza, and other fungi, 

 presently so-called, which are parasitic on the thallus of 

 various familiar lichens will ultimately be found to belong 

 themselves to the ranks of the lichens. I attribute, how- 

 ever, no blame to my predecessors for having erred in regard 

 to the structure and place in classification of these minute 

 organisms. Nay, I do not see how such ei'rors coidd have 

 been avoided; for the parasitic lichens, to which I refer, 

 could not have been properly studied prior to the introduc- 

 tion of the microscope. I believe it to be too common 

 now-a-days to depreciate the labours of the earlier botanists; 

 but the more we study the minuter Cryptogams the more 

 must we become convinced of the extent, accuracy, and value of 



