It is a variable species and hence has been known under so many names.
It grows to a height of 70 to 80 feet, and a diameter of 2 to 3 feet,
though larger trees are not infrequently found. Its large spreading
branches form a broad, round, open top.
The _bark_ is rough, though not deeply furrowed and varies from light
gray on younger trees to dark or almost black on older ones.
The _leaves_ are of two different types: (1) irregular-shaped lobes,
mostly narrow, bristle-tipped, the central lobe often the longest; or
(2) pear-shaped with 3 rounded lobes at the outer end. They are dark
lustrous green above and gray downy beneath, the contrast being
strikingly seen in a wind or rain storm.
The _flowers_ appear in April while the leaves are unfolding. The
_fruit_ ripens the second year. The small rounded acorn, about half an
inch long, is set in a thin saucer-shaped cup which tapers to a short
stem.
The _wood_ is heavy, hard, strong, coarse-grained and is less subject to
defects than most other red oaks. It is used for rough lumber and for
furniture, chairs, tables, etc. It is a desirable timber tree,
especially on the poorer, drier soils. The bark is rich in tannin.
_Q. rubra_ var. _pagodaefolia_, called swamp Spanish oak, has been
collected in four southern counties of Illinois.
+BLACK JACK+ _Quercus marilandica_ Muench.
THE black jack oak is a tree of sandy and clayey barren lands where few
other forest trees thrive. It ranges from New York to Florida and
westward into Illinois, Arkansas, and Texas. It reaches its largest size
in southern Arkansas and eastern Texas. It is found as one of the main
species in the "Post Oak Flats" in the southern half of the State and in
the sands along the Illinois River, near Havana. The tree sometimes
reaches a height of 50 to 60 feet and a diameter of 16 inches, but it is
usually much smaller. Its hard, stiff, drooping branches form a dense
crown which usually contains many persistent dead twigs. The _bark_ is
rough, very dark, often nearly black, and broken into small, hard scales
or flakes.
[Illustration: BLACK JACK OAK