xxviii Proceedings. 
wood, because of its extreme lightness and that it was obtained 
from a small tree, which belonged to the genus Leitneria, of 
which one species has been described from the swamps of 
Florida, where it becomes a shrub, while one or two refer- 
ences have been made to a similar or identical species collected 
in scanty specimens in southern Texas and the adjoining part 
of Mexico. 
The specific gravity of our native woods as reported in 
Prof. Sargent’s volume on the forests of the United States, 
ranges from 0.2616 (Ficus aurea) to 1.302 (Condalia ferrea ), 
both from Florida, —the greater number of species lying 
between 0.40 and 0.80. One Indian wood has been reported 
as having a specific gravity of 0.260, but so far as the speaker 
could learn, no wood of lower specific gravity than this has 
ever been observed. The cork wood collected by Mr. Bush 
was so extremely light that at the request of the speaker 
Prof. Nipher had some time since made a determination of its 
specific gravity which he found to be 0.207, or almost exactly 
one-fifth the density of water. According to the statement 
in Ganot’s Physics, cited by Prof. Nipher, the density of cork 
is given as 0.24, so that this Leitneria wood proves to be not 
only very much lighter than the lightest wood of which 
record could be found, but also very much lighter than the 
commercial cork. 
A series of photosicrographs, illustrating the structure of 
the cork wood were exhibited, showing in the thin walled cells 
a reason for this low specific gravity, and the speaker called 
_ attention to the light thrown by a sicroscopical examination 
upon the affinities of the plant, making reference to the views 
of Chapman, Baillon and Benthan and Hooker, and of Van 
Tieghem and Lecomte, who some years since made a histori- 
cal study of the wood of the Floridan plant. 
Mr. Bush, who was present, was introduced to the Academy, 
and gave an account of the region in which this Leitneria 
occurs, making reference to the large number of Floridan 
species which tid Bien discovered in the southeastern part of 
Missouri during his collecting trips in the interest of the 
Botanical Garden and the World’s Fair Commission of 
Missouri. 
