SCIENTIFIC PAPERS. 
JUGLANDACEAE OF THE UNITED STATES. 
BY WILLIAM TRELEASE. 
In 1893-4, a study of the North American Juglandaceae 
was made, which led tu the preparation of a synoptical re- 
vision of the species occurring in the United States, but as 
several supposed hybrids had been received in fruit, which 
it was desirable to have represented by material show- 
ing flowers and foliage, the manuscript was laid aside 
for a year and again taken up in the fall of 1894. At that 
time, however, more fruiting material requiring additional 
summer collections was received, so that the revision, as 
then completed, was again laid aside. In February, 1895, 
the seventh volume of Professor Sargent’s Silva of North 
America appeared, so that it is not now considered desir- 
able to publish the entire manuscript I had prepared. The 
following pages, therefore, contain merely such a tabula- 
tion of the fruit, twig, bark and bud characters as it is 
thought will be helpful in field studies, with notes on the 
hybrid forms referred to. 
In a memoir published in 1862,* as well as in a descriptive 
monograph of the Juglandaceae,t M. De Candolle makes use 
of certain characters derivable from the winter buds, by 
which not only the large groups but even some species of 
hickory may be distinguished; and, in fact, most of the 
species are more readily known in their winter condition 
than during the period of flowering or the early summer 
season. This is also true of the walnuts, where differences 
* Annales des Sciences naturelles, Bot., ser. 4, xviii. 1. 
¢ DC. Prodromus, xvi. (2), 142, 144. 
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