Spring Flora of Oklahoma 
29 
FAMILY 13. ULMACEJE. Elm Family. 
Trees or shrubs with watery juice. Alternate, simple, 
petiolate, serrate, stipulate leaves, which are usually 2- 
ranked. Small, bi-sexual, or somewhat monoecious, apet- 
alous flowers. Calyx of 3-9 sepals, which are distinct or 
partly united. Stamens as many as the sepals and op¬ 
posite them. Ovary 1-2 celled. Styles 2, spreading. Fruit 
a key, nut, or drupe. 
Flowers borne in clusters on twigs of the preceding 
season; fruit a samara, or nut-like. 
Flowers mostly expanded before the leaves; calx 4-9- 
cleft; fruit a samara. I. Ulmus. 
Flowers expanding with the leaves; calyx 4-5-cleft; 
fruit nut-like. II. Planera. 
Flowers borne on twigs of the season, the pistillate 
mostly solitary; fruit a drupe. III. Celtis. 
I. ULMUS L. 
\ 
Trees with straight-veins, unsymmetrical, doubly ser¬ 
rate leaves. Stipules early deciduous. Flowers bi-sexual. 
Calyx bell-shaped, 4-9-cleft. Stamens slender, protrud¬ 
ing. Ovary compressed. Styles 2, spreading. Fruit 
membranaceous flat, winged on the edge. Leaves smooth 
or slightly rough above; samara densely ciliate. 
None of the branches corky-winged; samara? faces glab¬ 
rous. 1. U. americana. 
Some of the branches corky-winged; samara-faces pub¬ 
escent. 2. JJ. (data. 
Leaves very rough above; samara not ciliate; twigs not 
corky-winged. 3. U. fulva. 
1. Ulmus americana L. American or White Elm. Leaves oval 
or obovate, apex abruptly acuminate, base obtuse or obtusish, and 
very inequilateral, sharply and usually doubly serrate, smooth or 
