This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
A tree, similar to the elm, the flowers monoecious or polygamous, unfolding with the leaves. Staminate flowers fascicled on twigs of the preceding season, the pistillate or perfect ones in the axils of the leaves of the year. Calyx 4-5-cleft, campanulate, persistent, the lobes imbricated. Filaments filiform, straight, exserted. Ovary stalked, ovoid, slightly compressed, 1-celled. Styles 2, spreading, stigmatic along the inner side. Fruit nut-like; coriaceous, obliquely ovoid, compressed, ridged on the back, covered with short fleshy processes. Embryo straight. [Name in honor of Johann Jakob Planer, 1743-1789, Professor of Botany in Erfurt.]
A monotypic genus of southeastern North America.
A small tree, sometimes 400 high, and with a trunk 2° in diameter, the foliage nearly glabrous. Leaves ovate or oblong-lanceolate, acute at the apex, obtuse or cordate and usually somewhat inequilateral at the base, serrate, l'-2' long; petioles 1 1/2"-2" long; stipules lanceolate, about as long as the petioles, deciduous; staminate flowers fascicled and somewhat racemose from scaly buds borne at the axils of leaves of the preceding season; perfect or pistillate flowers on short branches; fruit 2"-3" long, about equalling its stalk, its soft processes 2" long.