8 HISTORY OF LICHENOLOGY 



5- "Coriacei"; 6. "Scyphiferi"; 7. "Filamentosi." By this ordered sequence 

 Linnaeus showed his appreciation of development, beginning, as he does, 

 with the leprose crustaceous thallus and continuing up to the most highly 

 organized filamentous forms. He and his followers still included the genus 

 Lichen among Algae. 



A voluminous History of Plants had been published in 175 1 by 

 Sir John Hill\ the first superintendent to be appbinted to the Royal 

 Gardens, Kew. In the History lichens are included under the Class 

 "Mosses," and are divided into several vaguely limited "genera" — Usnea, 

 tree mosses, consisting of filaments only; Platysma, flat branched tree 

 mosses, such as lungwort; Cladonia, the orchil and coralline mosses, such as 

 Cladoniafurcata ; Pyxidium, the cup-mosses; and Placodium,the crustaceous, 

 friable or gelatinous forms. A number of plants are somewhat obscurely 

 described under each genus. Not only were these new Lichen genera sug- 

 gested, by him, but among his plants are such binomials as Usnea compressa, 

 Platysma corniculatum, Cladonia furcata a.nd Cladonia top hacea; other lichens 

 are trinomial or are indicated, in the way then customary, by a whole sen- 

 tence. Hill's studies embraced a wide variety of subjects; he had flashes of 

 insight, but not enough concentration to make an effective application of 

 his ideas. In his Flora Britannica^, which was compiled after the publication 

 of,Linnaeus's Species Plantarum, he abandoned his own arrangement in 

 favour of the one introduced by Linnaeus and accepted again the single 

 genus Lichen. 



Sir William Watson^, a London apothecary and physician of scientific 

 repute at this period, proposed a rearrangement and some alteration of 

 Linnaeus's sections. He had failed to grasp the principle of development, 

 but he gives a good general account of the various groups. Watson was the 

 progenitor of those who decry the makers and multipliers of species. So in 

 regard to Micheli, who had increased the number to "298," he writes: "it is to 

 be regretted, that so indefatigable an author, one whose genius particularly 

 led him to scrutinize the minuter subjects of the science, should have been 

 so solicitous to increase the number of species under all his genera: an error 

 this, which tends to great confusion and embarassment, and must retard the 

 progress and real improvement of the botanic science." Linnaeus however 

 in redressing the balance earned his full approbation: "He has so far 

 retrenched the genus {Lichen^) that in his general enumeration of plants he 

 recounts only 80 species belonging to it." 



Linnaeus's binomial system was almost at once adopted by the whole 

 botanical world and the discovery and tabulation of lichens as well as of 

 other plants proceeded apace. Scopoli's* Flora Carniolica, for instance, 

 published in 1760, still adhered to the old descriptive method of nomen- 

 iHilli75i. 'RiW's, germs, Collema\s,Nostoc, etc. ''Hill 1760. * Watson 1759. * Scopoli 1760. 



