PREFACE. Xlv 



The mode in which the tables of this book are to be employed will be 

 best explained by an example, the reader being supposed to be in j)osses- 

 sion of the preliminary knowledge which is afforded by the Introduc- 

 tion. Let a Cistus be the subject of inquiry. Upon examining the tables, 

 the first question which tbe student must ask himself is, Whether it belongs 

 to Vascular or Cellular plants, to Dicotyledons or Monocotyledons : the 

 structure of the leaves tells him this, and he decides for Dicotyledons. He 

 next inquires if it has the seeds naked or in a capsule ; and ascertaining 

 that the latter is the case, ha knows it belongs to Angiospermae. He then 

 finds it to be polypetalous, and that the stamens are hypogynous, or those 

 of the division called Thalamiflor*. Having proceeded thus far, he is led 

 to inquire whether the carpella are in a state of combination, or distinct ; 

 and finding the former to be the case, he sees that his plant is referable to 

 what are called Syncarpae, among Polypetalous Dicotyledons with hypo- 

 gynous stamens. Now the artificial divisions of this section are seen to 

 depend, in the first instance, upon the structure of the ovarium : that organ 

 is examined, and is found to be 1-celled, with the ovules parietal. Among 

 plants of this nature, the placentae are either linear and contracted, or 

 branched all over the surface of the valves ; there is no difficulty in ascer- 

 taining this point, and it is found that the plant in question has the former 

 character. Then comes an inquiry whether the sepals are 2, or invaria- 

 bly 4, or 5 (occasionally varying to 4, 6, or 7) ; they are found to be 5 ; 

 and here the analysis is reduced to the decision between whether the ovules 

 have a foramen at the extremity opposite the hiluin, or next the hilum ; 

 the former being ascertained to be the case, no doubt can remain of the 

 plant belonging to the natural order Cistinece. This operation may appear 

 rather tedious, but after a little practice it is gone through quickly ; and 

 when the conclusion sought for is attained, the station of the plant is not 

 only ascertained, but also that all vegetables having the same characters 

 are herbaceous or shrubby plants, with gay ephemeral flowers, usually 

 growing in rocky places, and possessing no known qualities except that 

 of secreting, in some instances, a sort of resinous substance used as a 

 stomachic and tonic. 



Examples need not be multiplied, one instance showing what the 

 method of analysis is, as well as more. 



The plan adopted, independently of the part now adverted to, is this : 

 To every collection of orders, whether called class, division, subdivision, 

 tribe, section, or otherwise, such remarks upon the value of the characters 

 assigned to it are prefixed as the personal experience of the Author, or 

 that of others, shows them to deserve. To every order the Name is given 

 which is most generally adopted, or which appears most unexceptionable, 

 with its Synonymes, a citation of a few authorities connected with each, 

 and their date : so that, from these quotations, the reader will learn at 



