State. Others are large technical taxonomic references to all known 

 species. Most have both descriptions and illustrations, commonly line 

 drawings, less frequently photographs, while some add distribution 

 maps. Others are merely keys or lists for identification. An evaluation of 

 State tree guides was made by Andresen (1961 A). 



Publications on both wild plants and cultivated plants are cited. Most 

 references for identification of woody plants are limited to the native 

 species. Many add escaped and naturalized species, which are relatively 

 few. However, some titles mention that coverage includes cultivated 

 plants, and many are so restricted (E. Cultivated Woody Plants, page 

 12). 



Most references are for identification during the growing season and 

 stress the botanical characteristics of flowers, fruits, and leaves. Others 

 for the dormant season or winter add bud, twig, bark, etc. (J. a. Identifi- 

 cation in Winter, page 48). A few serve to name the stages of seeds and 

 seedlings (J. b. Seeds and Seedlings, page 49). 



References excluded. Some titles have been omitted because of their 

 broader scope. Examples are the floras and manuals of flowering plants, 

 which can be located through other bibliographies (A. Bibliographies, 

 page 5). These books contain trees and shrubs and are useful in identifica- 

 tion, particularly in localities not well covered by special publications for 

 woody plants. However, the greater part of these volumes is devoted to 

 the much larger number of species of herbaceous or nonwoody plants. 

 Guides to wildflowers contain few woody plants and are omitted also. 



Most lists of species and catalogs have been excluded except under B. 

 Check Lists (page 6). Publications on wood identification have not been 

 cited. References for children, or of juvenile literature, have been omit- 

 ted but can be found in schools and public libraries. 



Many books and bulletins are devoted to the selection, planting, and 

 care of cultivated woody plants, particularly ornamentals, and fall out- 

 side the scope of this compilation. Some of these related references are 

 well illustrated in color. Several that are useful also for identification 

 have been added. Incidentally, a few titles from foreign countries that 

 have been adapted or translated for the United States have not been 

 cited. Additional bulletins and circulars about cultivated trees, shrubs, 

 and woody vines, including ornamentals and fruits, have been issued by 

 State Agricultural Experiment Stations. 



Publications for identifying the many cultivated varieties (cultivars) of 

 woody plants, especially ornamentals and fruits, likewise are omitted. 

 Some of these references treat in detail a single group or genus, such as 

 roses (Rosa), azaleas (Rhododendro?i), and lilacs (Syringa). 



Editions and reprints. Many publications, especially State tree 

 guides, have been revised and reprinted at various times through the 

 years. The aim has been to list the latest edition and the year of the last 

 revision. The only changes of some titles are the dates. Several old 

 references have been reprinted, often with an added list or supplement of 



