192 ULMACEAE 
of the envelope. Ovary 1-celled, above the envelope. Fruit a dry 
nut-like winged body. 
Flowers opening before the appearance of leaves. . . Ulmus 
Flowers opening after the appearance of the leaves . Celtis 
17 ULMUS, L. 
Leaves alternate, with oval, sharply notched leaves, which are unequal 
on the two sides of the midvein. Staminate flowers in tufts of reddish- 
brown, small, bell-shaped (Fig. 5, pl. 30). Seeds in samaras or dry, flat, 
ovoid, winged encasements which float in the wind or drop at the foot of 
the tree (Fig. 4, pl. 30). 
Flowers without pedicels (sessile on the stem) . . .« « « « « « Uz. fulva 
Flowers on pedicels. 
Bark of twigs smooth PP ae Or rine Suc te OLS U. americana 
Bark of twigs with corky wings or ridges . . . . . . U. racemosa 
1. U. fulva, Michx. Stiepery Erm. Rep Erm. A tree 45 to 60 ft. 
high; leaves oval or ovate, one side much shorter than the other, ser- 
rations double, the apex slender tapering, upper surface very rough with 
short papillae, under surface downy, length 5 to 7 in. by 2 to 3 in. broad. 
The roughness of the leaves of this elm is felt whether the hand passes 
from stem to point or in the opposite direction. Those of No. 2 feel 
rough only in passing the hand from apex to stem. New England and 
westward. 
2. U. americana, L. (Figs. 4 and 5, pl. 30.) AMERICAN ELM. 
Wuite Erm. The more common species. Leaves similar to No. 1 but 
on the whole smaller, rough only one way. Common. 
3. U. racemosa, Thomas. Cork Erm. Rock Exim. Leaves similar 
to those of Nos. 1 and 2 but the serrations are finer and the base of the 
leaf is more rounded. Corky ridges often appear on twigs which are 
more than a year old. New England and westward. 
2. CELTIS, L. 
While the leaves of the elms have a single main vein extending through 
the center from which feather veins run from each side with much 
regularity, in Celtis the leaves have 3 main veins with lesser veins 
coursing in various directions. Flowers greenish, the staminate in clus- 
ters of several flowers, the pistillate solitary or 2 or 3 together. Calyx 
of 4 to 6 segments. Fruit a globular berry. 
1. C. occidentalis, L. (Fig. 6, pl. 30.) AMERICAN NETTLE TREE. 
Hackperry. ‘Tree resembling an elm with sweet fruit. Leaves egg- 
shaped with reticulate veinings from 3 main veins; serrations single, 
coarse. Staminate flowers numerous on drooping pedicels; pistillate 
usually solitary. Some of the flowers have both stamens and pistils. 
Var. C. occidentalis crassifolia, Lam. Hackserry. Tree or shrub with 
downy twigs and egg-shaped leaves which are rough above. Otherwise 
much like 0. occidentalis. New York and southward. 
