308 NEW ENGLAND TREES IN WINTER. 



The photographic illustrations are all originals, most of them 

 by the other author. Although one of us is responsible for the 

 text and for the selection of the material photographed and the 

 other for the photographs, we have freely consulted and the 

 bulletin is therefore to be considered a joint publication. 



The order of arrangement of the species in the text and the 

 scientific names follow the usage of the seventh edition of Gray's 

 Manual and the latter are in accord with the rules laid down in 

 the Vienna Congress. The figures and descriptions given are of 

 trees for the most part growing wild in New England. A few 

 rarer species which occur in New England only very locally or in 

 isolated instances have been omitted from illustration. In their 

 places, however, some of the more frequently cultivated trees, have 

 been included because of their value for forestry planting in New 

 England or because of their familiarity in city ornamental plant- 

 ings. The varieties of cultivated forms are so numerous that it is 

 obviously possible to take account of only the most common types. 

 Their inclusion, it is believed, will add to the value of the publi- 

 cation especially for its use in cities. The keys can be absolutely 

 relied upon only for the species just mentioned from New England. 

 New England, including as it does the meeting ground between 

 the northern and southern floras, is extremely rich in the species 

 of trees represented. The bulletin, therefore, especially in its 

 descriptive text and illustrations should prove of service outside of 

 the geographically restricted region described. 



The final keys to the genera and to the species as well as the 

 descriptive text in galley were placed in the hands of the present 

 year's classes in Botany and Forestry. A student after finding 

 the species by the keys, read the twig characters in the galley 

 and signed his name opposite the species if the description corres- 

 ponded with the twigs supplied. All of the trees described and 

 illustrated have thus been checked up by students and some of them 

 by as many as seventy different persons. In this way limitations 

 to the use of certain of the characters employed as means of 

 separating allied species have been discovered and the constancy 

 of other characters has been confirmed in so far as the material 

 available could allow. The greatest assistance rendered by the 

 students, however, has been in disclosing difficulties in the use of 

 the keys, due to unfortunate choice of contrasted characters or of 



