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bois inconnu, common hackberry, hackberry, micocoulier occidental, western hackberry

elm family

Habit Trees or shrubs, size varying greatly in response to habitat; crowns rounded. Trees or shrubs, deciduous (sometimes tardily deciduous in Ulmus).
Bark

gray, deeply furrowed, warty with age.

smooth to deeply fissured or scaly and flaky;

sap watery.

Branches

without thorns, spreading, young branches mostly pubescent.

Leaves

blade lance-ovate to broadly ovate or deltate, 5-12 × 3-6(-9) cm (on fertile branches), leathery, base oblique or obliquely somewhat acuminate, margins conspicuously serrate to well below middle, teeth 10-40, apex acuminate;

surfaces scabrous.

blade: base often oblique, margins entire or serrate, crenate, or toothed;

venation pinnate to palmate-pinnate.

Inflorescences

dense pendulous clusters.

axillary, cymes, racemes, fascicles, or flowers solitary, arising from branchlets of previous season (e.g., Ulmus) or of current season (e.g., Celtis).

Flowers

bisexual or unisexual, staminate and pistillate on same [different] plants;

sepals persistent, (1-)5(-9), connate [distinct], imbricate or valvate;

petals absent;

stamens usually as many as calyx lobes, hypogynous, opposite calyx lobes, erect in bud;

filaments free or arising from calyx tube, distinct, curved or sigmoid in bud;

anthers 2-locular, dehiscence longitudinal;

pistils 1, 2(-3)-carpellate;

ovary 1(-2)-locular;

ovules 1 per locule, pendulous from apex of locule, anatropous or amphitropous;

styles (1-)2, distinct, receptive stigmatic area decurrent on distal inner margin of style branch.

Fruits

fleshy drupes, samaras, or nutlike.

Drupes

dark orange to purple- or blue-black when ripe, orbicular, to 7-11(-20) mm diam., commonly with thick beak;

pedicel to 15 mm.

Seeds

1;

arils absent;

endosperm absent to scanty, consisting of 1 layer of thick-walled cells;

embryo straight or curved.

Wood

light yellow, weak.

Stones

cream colored, 7-9 × 5-8 mm, reticulate.

2n

= 20, 30, and 40.

Celtis occidentalis

Ulmaceae

Phenology Flowering late winter–spring (Mar–May).
Habitat In rich moist soil along streams, on flood plains, on rock, on wooded hillsides, and in woodlands
Elevation 0-1800 m (0-5900 ft)
Distribution
from FNA
AL; AR; CO; CT; DC; DE; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; MB; ON; QC
[WildflowerSearch map]
[BONAP county map]
Tropical and north temperate regions
[BONAP county map]
Discussion

Celtis occidentalis is valued as an ornamental street tree because of its tolerance to drought.

Native Americans used decoctions prepared from the bark of Celtis occidentalis medicinally as an aid in menses and to treat sore throat (D. E. Moerman 1986).

This is a highly variable species. Segregates named as varieties follow an east-west geographic gradient and are based primarily on leaf size, shape, and pubescence.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera ca. 18, species ca. 150 (4 genera, 19 species in the flora).

Plants of this family are wind-pollinated (anemophilous).

Ulmaceae are frequently divided into two subfamilies, Ulmoideae and Celtoideae; they are sometimes separated into two families, Ulmaceae and Celtidaceae (I. A. Grudzinskaya 1965). These subfamilial or familial distinctions are supported by flavonoid chemistry (D. E. Giannasi and K. J. Niklas 1977; D. E. Giannasi 1978), pollen morphology (M. Zavada 1983), and some anatomic structures (E. M. Sweitzer 1971). Typically the Ulmoideae have flavonols, strictly pinnately veined leaves, and dry fruits; the Celtoideae have glycoflavones, pinnipalmately veined leaves, and drupaceous fruits. Some genera (e.g., Zelkova, with pinnately veined leaves and drupaceous fruits) are intermediate, and various authors place them in different subfamilies.

In this treatment Ulmus and Planera are considered part of the subfamily Ulmoideae; Celtis and Trema are in subfamily Celtoideae. Zelkova serrata is widely cultivated as an ornamental tree in North America, but it is not known to be naturalized in the flora. Chemical similarities between subfamilies include the presence of proanthocyanins with some tannins and scattered mucilaginous cells or canals. Additionally, members of the family share a strong tendency toward mineralization of the cell walls with calcium carbonate or silica and possess solitary or clustered crystals of calcium oxalate.

Ulmaceae include trees and shrubs of horticultural importance.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Leaf blade pinnately veined; fruits dry, nutlike or samaras.
→ 2
1. Leaf blade palmately veined at base, pinnately veined over remainder of blade; fruits drupes.
→ 3
2. Flowers bisexual; fruits samaras.
Ulmus
2. Flowers normally unisexual, inflorescences usually with a few bisexual flowers; fruits nutlike.
Planera
3. Leaf blade entire or serrate to ca. 3/4 length; flowers solitary or in few-flowered clusters; drupes 1.
Celtis
3. Leaf blade crenate to serrate for entire length; flowers 12-20, in cymes.
Trema
Source FNA vol. 3. FNA vol. 3, p. 368. Authors: Susan L. Sherman-Broyles, William T. Barker, Leila M. Schulz.
Parent taxa Ulmaceae > Celtis
Sibling taxa
C. laevigata, C. lindheimeri, C. pallida, C. reticulata, C. tenuifolia
Subordinate taxa
Celtis, Planera, Trema, Ulmus
Synonyms C. occidentalis var. canina, C. occidentalis var. crassifolia, C. occidentalis var. pumila, C. pumila, C. pumila var. deamii
Name authority Linnaeus: Sp. Pl. 2: 1044. (1753) Mirbel
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