EXPLANATIONS 



The main account of each genus, in large type and 

 separate paragraph for each species, represents the 

 plants probably now in cultivation or at least of major 

 importance. 



The "supplementary lists" in smaller type at the end 

 ' if the articles include names of plants not known to be 

 in the trade but which may be mentioned in horticul- 

 tural literature, and also such Latin-form names of 

 the trade as are imperfectly understood and cannot be 

 placed under their proper species. These parts are less 

 critical finding-lists of other or extra species. 



The Cyclopedia undertakes to account for the 

 species in cultivation within its territory to the close 

 of the year 1912; but in practice the introductions are 

 included to the date of the closing of the different 

 pages. 



The size-marks on the illustrations, as (x Vz), 

 indicate the amount of reduction as compared with 

 natural size, this scale being determined merely by 

 measuring the flat diameter of a drawing and not 

 representing bulk or perspective. 



AUTHORSHIP 



The practice of the Cyclopedia of American Horti- 

 culture in signing the leading and most important 

 articles with the name of the author is here retained. 

 The original author, so far as living or as he has desired, 

 has revised or rewritten his articles for the present work. 

 In very many cases, another person has now revised the 

 articles, and the name of the reviser is indicated by a 

 dagger (t). If the revision has amounted practically 

 to a complete rewriting of the article, the original 

 author's name may not appear, even though some small 

 parts or features of the original article may be retained; 

 this is for the purpose of safeguarding the original 

 author as well as recognizing the work of the present 

 author: the first Cyclopedia stands as the record of its 

 own work. 



A name in parentheses, as "(G. W. Oliver)," at the 

 close of a paragraph, indicates that the person is the 

 author of that particular paragraph and of no other in 

 the article. When a person is responsible for more than 

 one paragraph in an article, his part is set off by a sepa- 

 rate heading in such a way that it cannot be mistaken. 



It is desired to secure experts and specialists for the 

 articles; when this has not been accomplished, the task 

 of revision has fallen to the Editor. 



Effort has been made to bring the different parts of 

 the work into as much uniformity of plan and treatment 

 as is possible in an undertaking of this kind; references 

 have been compared; proofs have been submitted to 

 two or more persons in case of difficult or doubtful sub- 



jects; and the advice as to cultivation has been checked 

 by practical growers. 



NOMENCLATURE 



The nomenclature follows in the main the regu- 

 lations of the "Vienna code," being the principles, 

 adopted by the International Botanical Congress held 

 in Vienna in 1905. This code was adopted by the 

 International Horticultural Congress held at Brussels 

 in 1910, with adaptations to horticultural practice. 

 When no combination has yet been made under the 

 Vienna code, the prevailing usage for the particular 

 genus (as expressed in latest monographs) is followed. 

 That is, there is no attempt to reduce all names to one 

 system except so far as combinations have already 

 been made under the international rules, both because 

 a cyclopedia of horticulture is hardly the place in 

 which to make original combinations (except inci- 

 dentally), and because there is little likelihood that 

 any of the formal systems will have permanency. The 

 subject of nomenclature, and the attitude of the Editor, 

 will be discussed under "Names and Nomenclature" 

 in Vol. IV. Botanical names should not be changed 

 lightly, or for the purpose of regularizing any particular 

 scheme or plan, or to make them always conform to 

 an arbitrary set of rules. Botanical names do not be- 

 long to botanists, to do with them as they will. The 

 public has good rights in these names; and this is par- 

 ticularly true in the names of cultivated plants, for they 

 may then have standardized commercial value. The 

 only stability, of course, is usage; and usage can rarely 

 be forced into hard-and-fast regulations. In this Cyclo- 

 pedia, the interest is in stability of names rather than 

 in priority of nai.ies; therefore it accepts the principle of 

 the "noniina conservanda" of the Vienna code, so far as 

 it retains generic names that have been established in 

 general usage for fifty years following their publication, 

 even though the particular names in that list may not 

 have been adopted in every instance. 



Not all the changes in names arise from the applica- 

 tion of rules of nomenclature. Many of them are the 

 results of taxonomic studies, which make new definitions 

 for genera and species. In this Cyclopedia, there are 

 marked examples of such changes in the citrus genera, 

 in the cacti, and other groups. These changes are to 

 be expected as a result of closer studies of the various 

 groups, of accumulation of specimens from many 

 regions, and the progressive modification of views as 

 to the constitution of genera and species; they are 

 expressions of a living botany. Such changes will be 

 particularly demanded in horticultural plants, for 

 most of these groups have not yet been studied with 

 critical care. 



(xi) 



