Preface to Volume III. 



WITH the publication of the concluding volume of the Illustrated Flora, the authors 

 desire to express their appreciation of the favor with which the previous volumes 

 have been received. Volume III, it is believed, will be found no less useful than the pre- 

 ceding ones; and from the difficulties presented to the student by the great family of Com- 

 posites, which occupies about one-half of the present volume, this may prove to be the most 

 helpful of all. 



The number of species figured in the whole work is 4162, comprising 177 Families and 

 1 103 Genera. Eighty-one of these species, mostly western, being new determinations or 

 new discoveries, made while the work has been going through the press and too late for in- 

 sertion in their proper places, are figured in the Appendix (pp. 484 to 521 ). These bring up 

 to January, 1898, it is believed, all well established species within our area. The cuts are 

 numbered consecutively throughout the work, except those in the Appendix, which are re- 

 ferred to their proper places by giving to each the number of the previously figured species 

 to which it is most closely allied, with the addition of the letter a, b or c, etc., for distinction. 



As respects the admission of new species, the aim has been to pursue a conservative 

 course, and to admit those only that upon continuous observation appear to bear the requi- 

 site tests of constancy and persistency in their distinguishing characters. In an illustrated 

 work, however, devoted to the reproduction of what is found in nature, it is better to err in 

 illustrating too many forms, rather than in giving too few. 



A general Key of the Orders and Families, prepared by Dr. Britton according to the 

 method followed in the Keys to the genera and species, will be found at the beginning of 

 the volume, preceded by a table of abbreviations of the names of botanical authors cited. 

 At the close is a glossary of the special botanical terms here used, followed by a complete 

 General Index of all the Latin names, including synonyms, used throughout the work. 



This general Key has been elaborated on the natural method, dividing the two subking- 

 doms of plants described in the work into Classes, Sub-classes, Orders and Families success- 

 ively. The Orders are not described in the work itself, but their principal distinguishing 

 characters are given in this key. The natural method adopted necessitates a considerable 

 number of exceptions to statements, owing to the varying degree of development of floral 

 organs in the derivation of plants from their ancestors; these exceptions are either noted 

 under the headings or indicated by cross-references. 



In using this key, or any of the keys to genera or to species, the student will often find, 

 in the analysis of a plant that it does not provide all the information necessary for its deter- 

 mination; this is generally owing to the incomplete condition of the specimen collected; it 

 may be in flower, while the characteristic differences between it and others are only to be 

 found in the fruit, or vice versa ; or the species may be dioecious, or polygamous, when its 

 other organs, perchance the characteristic ones, must be sought on another individual, and 

 there are various other causes for incompleteness. It is therefore earnestly recommended 

 that collections be carefully made, seeking to reduce as far as possible this more or less neces- 

 sary incompleteness. Where satisfactory material can not be obtained, it will usually be 

 found possible to reach the desired analysis by following out two or more lines of the key, 

 and by comparing the results reached with the descriptions to determine the family, genus 

 or species. The illustrations provide an almost indispensable aid in such cases. 



For the general English Index at the end of this volume, Judge Brown has compiled a 

 list of all the popular names of the plants belonging to our area, so far as obtainable, both 

 general and local, including also most of the English names of our plants that have been 

 heretofore used by botanical authors, as well as most of the older and the more modern Eng- 

 lish popular names of plants common to our area and to England. Hundreds of these lat- 

 ter names were brought to this country by the early English colonists, some of which are 

 still current here that are now disused there. 



A considerable number of the popular names are given in the text in connection with 

 the leading English name, or in the notes. Several thousand others, which could not appear 

 in the text, are printed in the Index in italics. These are referred to the. proper plant by the 

 number of the illustration or figure (f ). The list includes in all about 10,000 different plant- 

 names, and upwards of 12,000 references to the illustrations. It embraces all our plant- 



