VI PEEFACE. 



is necessary for two seemingly contradictory reasons, 

 namely : — the great tendency of many collectors to consider 

 native any plant found growing upon a spot where it is 

 not cultivated ; and the peculiar scepticism of some of our 

 botanists concerning the claims of many local or thinly 

 scattered species to be admitted as indigenous, even when 

 their distribution upon the European continent is not un- 

 favourable to the belief that they may inhabit Britain. It 

 has been recommended that the descriptions of these ex- 

 cluded species should be placed in an Appendix or even 

 omitted ; but as some of them are not unlikely to be observed 

 by collectors, it is more convenient that they should be 

 arranged wiHi their allies. Those who desire to obtain a 

 complete knowledge of the distribution of onr plants should 

 consult Watson's Cyhele Britanmca, and Moore & More's 

 Gybele Hibemica. 



As in the writings of even the most learned botanists the 

 characters of the Natural Orders are far from definite, a 

 concise Syivrpsis of the Genera according to the Linnean 

 method is given, by means of which all the convenience 

 supposed to be possessed by books arranged on that system 

 is afforded to the reader. 



Full characters of the Natural Orders are to be found in 

 most of the best ' Introductions to Botany ;' and it has 

 therefore not been considered advisable to give them in 

 detail in the present volume. In his definitions, the Author 

 has endeavoured to point out the characteristic marks, more 

 especially as far as British plants are concerned. 



In using this book the student will find it convenient to 

 pay attention to the italicized parts of the generic, and spe- 

 cific characters, and, if they are found to agree with the plant 

 under examination, then to compare it with the other parts 

 of those characters, and also with those of allied genera and 

 species. 



