Flower: Staminate flowers borne on catkins. Pistillate flowers borne on spikes. Appearing March through May.
Fruit: Acorns are in clusters of 3 to 5, maturing in one season. The nut is dark in color, 3/4 inch long and covered 1/3 by the cap. The cap is bowl-shaped and warty, termed "turbinate" by Harlow et al. Maturing in September of the first year.
Twig: Slender, gray and pubescent, with small, blunt, multiple terminal buds.
Bark: Rapidly developing red-brown furrows with small surface scales. Later, becoming black and very blocky.
Form: A medium-sized tree that can grow to massive proportions. Open-grown trees develop a huge rounded crown. The largest crowns may be 150 feet across.