Distinguishing Features: Pin Oak is recognized by its drooping lower branches and its small acorns.
WILLOW OAK
Quercus phellos L.
Growth Form: Medium tree to 75 feet tall; trunk diameter up to 3 feet; crown narrowly round-topped.
Bark: Reddish-brown, smooth at first, becoming irregularly and shallowly furrowed with age.
Twigs: Slender, smooth, reddish-brown; pith star-shaped in cross-section; leaf scars alternate but crowded near the tip of the twigs, half-round, slightly elevated, with several bundle traces.
Buds: Ovoid, pointed, smooth, up to ⅛ inch long.
Leaves: Alternate, simple; blades without lobes or teeth, narrowly lanceolate to narrowly oblong, with a bristle tip, narrowed to the base, up to 5 inches long, up to 1 inch broad, light green and smooth on the upper surface, usually smooth and paler on the lower surface; leafstalks up to ½ inch long, smooth or slightly hairy.
Flowers: Staminate and pistillate borne separately, but on the same tree, appearing as the leaves begin to unfold, minute, without petals, the staminate in slender, drooping catkins, the pistillate few in a cluster.
Fruit: Acorns solitary or 2 together, with or without a short stalk, the nut more or less spherical, pale yellow-brown, enclosed less than ¼ its length by the cup, the cup reddish-brown, finely hairy.