OF TAXODIUM DISTICHUM AND RELATED SPECIES 387 
or almost wanting in 7: imbricarium. The same differences are 
often observable in cultivated specimens. 
The general appearance of the trunk of 7. distichum is well 
shown in figure 48 of Schimper’s Pflanzengeographie, which is a 
full page half-tone reproduction of a photograph taken by Dr. H. 
J. Webber in Florida,* also by plate 8 and figure 30 of Professor N. 
S. Shaler’s paper on the fresh-water morasses of the United States 
in the Tenth Annual Report of the U. S. Geological Survey, and 
by plate 73 in Mr. Kearney’s recent paper on Dismal Swamp,t 
which is the same as Professor Shaler’s plate 8. 
Plate 68 of Mr. Kearney’s paper illustrates very well the char- 
acter which I have just assigned to 7, zmbricarum, and plate 9 of 
Professor Shaler’s paper, which was evidently photographed at 
about the same time and place, shows the same thing, though less 
distinctly. By comparing these plates with the illustrations of 7. 
distichum just cited, the difference is readily seen. Nothwith- 
standing the fact that this species is not mentioned by Mr. Kearney 
in his paper (and he has since told me that he is not acquainted 
with it), I am confident that his plate 68 and Professor Shaler’s 
plate 9 represent the true Zaxodium imbricarium. 1 find no other 
record of the occurrence of 7. zmbricarium in Virginia than these 
two illustrations, but Croom found it near Newbern, N. C., which 
is only about 100 miles from Lake Drummond, Virginia, where 
the photographs in question were taken. 
Whether the knees afford any’ diagnostic characters or not I 
am unable to state at present. Elliott mentions those of Z. mért- 
carium as being more abundant than those of T. distichum, but 
this may not be universally true. Professor Shaler (in the paper 
above cited) and perhaps other authors, have noted that Z. dzs- 
4ichum cannot live with its knees under water during the summer. 
This is probably not true of 7: imbricarium, for I have seen it in 
midsummer in ponds and creeks where no knees were visible, at 
least at the ordinary stage of water. The knees of 7. smbricarium 
Probably never become so large as those of 7. distichum. 
Physical tests show an appreciable difference in the wood of 
the two species. Dr. Filibert Roth, in one of the publications of 
* The same photograph is reproduced in Coulter’s ‘‘ Plant Relations,”’ as Fig. 91. 
ft Contr. U. S. Nat. Herb. 5: 321-550. pl. 65-77-f. 51-90. 6N. 1901. 
