FLORAS OF THE WORLD 7 



been supplemented in the annotation, usually in the form of a 

 parenthetical statement. The figures of longitude given are based 

 on the Greenwich meridian. The annotations in all cases are to be 

 regarded as supplementary to the title. 



Each publication is listed in full only once, but cross-references 

 are given immediately following the pertinent geographic heading. 

 It has not seemed necessary to provide cross-references from smaller 

 geographical units to the larger units of which they form a part, 

 and the latter should always be consulted as well. Except in a very 

 few cases, all of which are so indicated in the annotation, all the 

 works listed have been examined by one or both of the authors. The 

 comparatively few works that, from their titles, appear to be of 

 value, but which have not been examined or found reviewed, are 

 listed directly after the appropriate geographic heading. 



The arrangement adopted is an alphabetical-geographical one. 

 summarized in the table of contents. The Times Survey Atlas of 

 the World (London, 1922) has been followed in general for geo- 

 graphic boundaries. Xo great difficulty has been found in arrang- 

 ing the titles under readily intelligible geographic headings except 

 in the cases of Africa and Insular Floras. The difficulty in Africa 

 arises not so much from the numerous changes of name following 

 the World War, which were accompanied by relatively few and mostly 

 unimportant changes of boundaries, as from the great area covered 

 by some of the principal floras and from the vagueness of many of the 

 geographical divisions of Africa that do not correspond with politi- 

 cal boundaries. The residue of works that could not be definitely 

 placed under any of the recognized political divisions was finally 

 listed under the headings Sahara, South Africa (in general, the 

 region south of the Tropic of Capricorn), and West Africa (in gen- 

 eral, the region from Mauritania to Angola). Cross-references to 

 these are provided under the separate countries concerned, but re- 

 ciprocal references under these three nonpolitical divisions have not 

 been considered necessary. 



The arrangement of the very numerous insular floras has offered 

 particular difficulty. Some papers deal with the flora of the whole 

 or only a part of definite island groups, others with that of a single 

 island of a group or with several scattered islands or groups of 

 islands; and the boundaries of such commonly used geographic 

 terms as Melanesia, Micronesia, and Polynesia differ somewhat in 

 different atlases and are usually not clearly marked on actual maps. 

 The method finally adopted is that of listing under separate headings 

 papers dealing with an island group as a whole and those dealing 

 individually with any of its constituent islands when these are of 

 any considerable size. Papers treating of the flora of several islands 

 or groups of islands are almost always listed in full under the first 

 island mentioned. Cross-references are provided in all cases. All 

 the islands north of 40° north latitude in the Atlantic and 30° 

 north latitude in the Pacific are placed under the continents and 

 countries to which they belong (Greenland under Xorth America; 

 Iceland, Spitzbergen, Faroe Islands, etc.. under Europe; Aleutian 

 Islands under Alaska, and so on) ; the islands stretching from the 

 southern tip of Kamchatka to and including Formosa, also Hainan 

 and the Boain Islands, as well as Ceylon, under Asia; New Zealand 



