40 
it is rarely found fruiting in the main tracks. Lenzites vilas, Pk., is often 
found upon the White Oak ties of bridges. 
Chestnut, Castanea vulgaris, var. Americana, A. D C, No. 290. 
Each annual ring of wood, as seen in the photomicrograph of the 
transverse section, has one concentric circle of ducts, at least in the 
interior portion of each ring, and in other specimens a second and some- 
times a third occurs. Botanists recognize only one species; but in re- 
gard to structure and color of the wood two varieties are discernible. 
In one of the sections, taken from a tree grown near New York City, 
the effect of climatic conditions upon the character of tlie cells formed 
is readily traced. 
In order to show an entire section of this ring (from the second 
growth wood, the most desirable for ties) three plates of the size of the 
one presented (7 by 7 J) would be required. The section of this ring- 
was taken from near the heart of the tree, and exhibits the character- 
istic structure, though the ducts are only about one-third the usual size. 
The wood from which the photomicrographs of the other sections 
were taken is most suitable for ties. Surrounding the ducts and grow- 
ing with them are tracheids, which have a lumen from one-half to two- 
thirds the size of the cell ; but in some of the annual rings (from the 
same piece of wood) only a few of the tracheids are seen with a large 
lumen beyond the first row of ducts; there are also found tracheids 
with a small lumen and some fibers making up the rest of the ring, 
while in an adjacent ring the tracheids may form many rows beyond 
the ducts, the wood-fibers usually completing the ring. Wood formed 
of rings of the latter character is stronger and has a greater specific 
gravity than wood which is formed of annual rings, as first described. 
Under the microscope the distinction between the two grades is easily 
made; for in the wood composed mostly of fibers there are numerous 
cells, which in the alburnum (except in active growth) contains starch. 
The heavy lines of cells running down the page represent the medullary 
rays, which in this wood are mostly in single rows, the cells being 
placed one above the other. The medullary rays bend around the 
ducts, their cells being slightly flattened and curved. In the wood- 
fibers the medullary rays are intersected at right angles by numerous 
rows of cells which contain starch, as described above. In the radial 
section the cells crossing the page are those of the medullary rays, 
while on the left are seen the numerous tracheids which surround the 
ducts. On the right of the page are the longitudinally arranged wood- 
cells and traces of some of the smaller ducts. The ends of the medullary 
rays are seen to be composed of cells in single rows, and very numer- 
ous. The cells of this wood contain considerable tannin, and their size, 
with a comparatively large lumen, shows that the wood has a low speci- 
fic gravity, ranging from 0.36 to 0.56, the former occurring in large trees 
grown in dense forests, while thf latter is frequently found in small 
