Ulmus americana
Ulmus serotina
American elm, orme d'amérique, white elm
red elm, september elm
light brown to gray, deeply fissured or split into plates.
light brown to reddish with shallow fissures.
pendulous, old-growth branches smooth, not winged;
twigs brown, pubescent to glabrous.
spreading to pendulous, often developing irregular corky wings with maturity;
twigs brown to gray, pubescent to glabrous.
brown, apex acute, glabrous;
scales reddish brown, pubescent.
brown, apex acute, glabrous;
scales dark brown, glabrous.
blade oval to oblong-obovate, 7-14 × 3-7 cm, base oblique, margins doubly serrate, apex acute to acuminate;
surfaces abaxially glabrous to slightly pubescent, tufts in axils of veins, adaxially glabrous to scabrous.
blade oblong-obovate, 7-10 × 3-4.5 cm, base oblique, margins doubly serrate, apex acuminate;
surfaces abaxially yellow-gold soft-pubescent, pubescence absent from axils of veins, adaxially yellow-green, glabrous.
fascicles, less than 2.5 cm, flowers and fruits drooping on elongate pedicels;
pedicel 1-2 cm.
racemes, 8-12-flowered, long, to 5 cm;
pedicel 0.5-1 cm.
calyx shallowly lobed, slightly asymmetric, lobes 7-9, margins ciliate;
stamens 7-9;
anthers red;
stigmas white-ciliate, deeply divided.
calyx lobed almost to base, lobes 5-6;
stamens 5-6;
anthers yellow-red;
stigmas white, pubescent.
thickened, not inflated.
thickened, not inflated.
soft.
hard.
yellow-cream when mature, sometimes tinged with reddish purple (s range of species), ovate, ca. 1 cm, narrowly winged, margins ciliate, cilia yellow to white, to 1 mm.
light brown, ovoid to elliptic, 1-1.5 cm, narrowly winged, pubescent, margins densely ciliate, tip deeply notched.
= 56.
= 28.
Ulmus americana
Ulmus serotina
Ulmus americana is reported as widely escaped in Idaho, which is not part of the natural range of this taxon. It is occasionally cultivated outside its native distribution, and it has escaped sporadically from cultivation. It is also reported as naturalized in Arizona, but I have seen no specimens.
Ulmus americana is the state tree for Massachusetts and for North Dakota.
The American elm is susceptible to numerous diseases, including Dutch elm disease. Ulmus americana has been a street and shade tree of choice because of its fast growth and pleasant shape and size. The species still exists in substantial numbers both as shade trees and in nature.
Numerous infraspecific taxa have been recognized in Ulmus americana (A. J. Rehder 1949; P. S. Green 1964).
Native American tribes frequently used parts of Ulmus americana for a variety of medicinal purposes, including treatment of coughs and colds, sore eyes, dysentary, diarrhea, broken bones, gonorrhea, and pulmonary hemorrhage, as a gynecological aid, as a bath for appendicitis, and as a wash for gunwounds (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ulmus serotina is infrequent, and few populations are found outside of Tennessee. It reputedly is highly susceptible to Dutch elm disease (W. H. Duncan and M. B. Duncan 1988), and it is sometimes cultivated. Ulmus serotina hybridizes with U. crassifolia, and plants have been informally designated U. arkansana, an unpublished name. In Arkansas and Oklahoma where hybrid swarms are common, specimens are often difficult to assign to either taxon.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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