i 345 ] 



Several circumstances have caused a long delay in 

 the publication of the present volume, which, if 

 their recurrence should not be prevented, may ren- 

 der the completion of the work, according to its 

 original plan, very precarious. In the mean while, 

 the number of volumes originally proposed is now 

 finished, and the first 23 Classes are completed, as 

 well as the first Order of the 24th, Cryptogamia 

 Filices, the only one that required more study and 

 emendation than it has hitherto received. 



Of the remaining Orders, the Miisci have been de- 

 tailed in the Latin Flora Brntann'ica and Compen- 

 dium of the author, as well as in his English Bo- 

 tany ; and by other well-known writers, in two 

 editions of the Muscologia Britannica^ and the 

 Muscologiai Hiberniccr SpicUeghim, Still this 

 beautiful and interesting tribe of plants might prove 

 susceptible of much illustration to English readers, 

 and of some improvements relative to generic dis- 

 tribution, on principles too little studied by the 

 pursuers of superabundant discrimination, instead 

 of philosophical combinations. This is the bane 

 of natural science at the present day. Hence the 

 filum Ar'iadneuni is lost, or wilfully thrown away, 

 and a bandage darkens the sight of the teacher no 

 less than that of the student. 



The monograph of Dr. Hooker on British Junger- 

 tnaniiucy which, with their allies, constitute the 

 next Order to the Musri^ dilVuses a new light over 

 the whole of that Order. The works of Mr. Daw- 

 son Turner on Fuci^ and of Mr. Dillwyn on Con- 

 ferva\ have gone far to exhaust the species of those 

 tribes, an ap|)lication of scientific principles to the 

 settlement of their genera being all that is wanting. 

 The L'uhtn family, under the eontroul of the great 



