11. Quercus palústris Du Roi. Pin Oak. [Plate 50.] Medium to large trees with very tight bark, the furrows shallow and generally wide; twigs at first pubescent, soon becoming smooth and reddish-brown; leaves on petioles generally 1-5 cm. long, blades about 7-15 cm. long, usually about 2/3 as wide, sometimes as wide as long, ovate to obovate in outline, narrowed to broadly truncate at the base, the margins divided into 5-7 lobes by deep and wide sinuses, except leaves that grow in the shade, the sinus cuts the blade to more than half way to the midrib, the lobes are widest at the base, or sometimes widest near the apex, the lobes usually somewhat toothed or lobed and end in 1-7 bristle tips, leaves hairy when they first appear, soon becoming glabrate and a glossy dark green above, a paler green beneath and smooth except tufts of hairs in the axils of the principal veins; acorns sessile or nearly so, single or in clusters; nuts subglobose or ovoid, generally 10-12 mm. long, the ovoid form somewhat smaller, covered about 1/4 their length by the shallow cups; cups saucer-shape and generally flat on the bottom, those with the ovoid nuts are rounded on the bottom; scales pubescent on the back, and rounded or blunt at the apex.
Distribution.—Massachusetts, southwestern Ontario, Michigan to Iowa and south to Virginia and west to Oklahoma. Found in every county of Indiana. It is found only in wet situations where it is a frequent to a common tree. It prefers a hard compact clay soil with little drainage hence is rarely met with on the low borders of lakes where the soil is principally organic matter.
Remarks.—Wood similar to red oak, but much inferior to it. It is tardy in the natural pruning of its lower branches, and when the dead branches break off they usually do so at some distance from the trunk. The stumps of the dead branches which penetrate to the center of the tree have given it the name of pin oak. It is also sometimes called water oak, and swamp oak.
For street and ornamental planting it is one of the most desirable oaks to use. It is adapted to a moist soil, grows rapidly, and produces a dense shade. When grown in the open it develops a pyramidal crown.
The nut of this species always has a depressed form, except a tree or two in Wells County which produce ovate nuts which are cone-pointed, and in bulk about half the size of the ordinary form. This form should be looked for to ascertain its area of distribution.
QUERCUS PALUSTRIS Muenchhausen. (× 1/2.)
Acorns from different trees. Those on the left the common form, those on the right the rare form.