vox. L.} PHILOSOPHICAL TRANSACTIONS. 2ig 



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 embarass- 

 ment, and must retard the progress and real improvement of the botanic science. 



Dr. Haller retains Micheli's term, and enumerates l6o kinds in his Enume- 

 ratio Stirpium Helvetias; he divides them into 7 orders, according to the follow- 

 ing titles: 1. Lichenes corniculati et pixidati. — 2. Lichenes coralloidei. — 3. Li- 

 chenes fruticosi alii. — 4. Lichenes pulmonarii. — 5. Lichenes crustacei scutis flo- 

 ralibus ornati. — 6. Lichenes scutellis ornati. — 7- Lichenes crustacei non scutati. 

 The extensive number of the species, and the difficulty of distinguishing them 

 with a tolerable degree of certainty, has deterred Dr. Haller from adding so full 

 and complete a list of synonyms to the plants of this genus as he has elsewhere 

 done in that splendid work. Plate the 2d exhibits several elegant sorts of these 

 lichens. 



Linneus, and the followers of his method, who seem to have established their 

 generical character from Micheli's discoveries, retain also his generical title. 

 Micheli's passion for the multiplication of species is no where more conspicuous 

 than in the plants of this genus, which he has most enormously augmented to 

 the number of 298 species. The Swedish professor cannot be charged with this 

 foible: it is one of the excellencies of his writings, that they inculcate the re- 

 verse. He has so far retrenched this genus, that in his general enumeration of 

 plants he recounts only 80 species belonging to it. They are in this work divided 

 into 8 orders, according to the difference of appearance which they form by their 

 facies externa, little or no regard being had to what are usually called the parts 

 of fructification. 1. Lichenes leprosi tuberculati. — 2. Lichenes leprosi scutellati. 

 — 3. Lichenes imbricati. — 1. Lichenes foliacei. — 5. Lichenes coriacei. — 6. Li- 

 chenes scyphiferi. — 7- Lichenes fructiculosi. — 8. Lichenes filamentosi. 



Dr. Dillenius, in his work, intitled, Historia Muscorum, has divided this 

 Michelian genus into 3, under the names of usnea, coralloides, and lichenoides. 

 Under the word usnea he comprehends the hairy-tree mosses, among which are 

 the usnea of the shops, and the true usnea of the Arabians. Of these he de- 

 scribes 16 species. Under coralloides he describes 39 species, among which are 

 the cup mosses, and many others, disposed according to the following scheme: 

 Ordo 1. Fungi formia, non tubulosa, nee ramosa, 5. 

 Ordo 2. Scyphiformia, tubulosa, simplicia et prolifera. 



Series 1. Scyphis perfectioribus. 13. Cup mosses. 



Series 2. Scyphis imperfectis. 20. Horned mosses. 

 Ordo 3. Ramosa fruticuli specie summitatibus acutis multifariam divisis. 



Series 1. Species tubulosae. 30. Tubulous coralline mosses. 



Series 2. Species solidae. 39. Solid coralline mosses: among which is the 

 orchel. 



VOL. XI. K K 



