This section is from the book "Woody Plants In Winter", by Earl L. Core, Nelle P. Ammons. Also available from Amazon: Woody Plants in Winter.
Deciduous trees or shrubs. Twigs rounded, slender; pith small, white, round, closely chambered, or continuous except at the nodes. Buds sessile, solitary, ovoid, with about 4 scales. Leaf-scars alternate, crescent-shaped or elliptical;bundle-traces 1 or 3; stipule-scars narrow. Fruit an ovoid or globose drupe, the mesocarp thin, pulpy, the endocarp bony.
a. | Tree with buds 3-4 mm. long; drupes 8-11 mm. long | 1. | C. occidentalis |

Fig. 85. Celtis occidentais.

Fig. 86. Celtis pumila.
a. | Shrub with buds 1-2 mm. long; drupes 5-8 mm. long | 2. | C. tenuifolia |
1. C. occidentalis L. Hackberry. A tree 8-28 m.high, up to 7.5 cm. in diameter, the bark black, rough, corky-ridged or warty; buds 3-4 mm. long; drupes sweet and edible, 8-10 mm. in diameter, the flesh thin. Rich woods, Quebec to Idaho, south to Florida and Oklahoma (Fig. 85).
2. C. pumila Pursh. Dwarf Hackberry. A low straggling shrub, often fruiting copiously when but 6-9 dm. high; twigs brown; buds 1-2 mm. long; drupes globose. Dry slopes, Quebec to North Dakota,south to Georgia and Oklahoma (Fig. 86).
 
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