FNA: Ulmus crassifolia vs. Ulmus serotina

	Ulmus crassifolia	Ulmus serotina
	cedar elm	red elm, september elm
Habit	Trees, 24-27 m; crowns rounded to narrow.	Trees, to 21 m; crowns spreading, broadly rounded.
Bark	light brown with shallow ridges and large plates.	light brown to reddish with shallow fissures.
Branches	often with opposite corky wings; twigs reddish brown, pubescent.	spreading to pendulous, often developing irregular corky wings with maturity; twigs brown to gray, pubescent to glabrous.
Buds	brown, apex acute, pubescent; scales dark brown, shiny, glabrous.	brown, apex acute, glabrous; scales dark brown, glabrous.
Leaves	blade ovate to elliptic, 2.5-5 × 1.3-2 cm, base oblique or rounded to cuneate, margins crenate to doubly serrate, apex obtuse; surfaces abaxially softly pubescent, adaxially harshly pubescent.	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.
Inflorescences	fascicles, 2-5-flowered, 0.5 cm; pedicel 0.75-1 cm.	racemes, 8-12-flowered, long, to 5 cm; pedicel 0.5-1 cm.
Flowers	calyx deeply lobed, more than 1/2 its length, lobes 6-9, hairy; stamens 5-6, anthers reddish purple; stigmas white, pubescent, exserted and spreading.	calyx lobed almost to base, lobes 5-6; stamens 5-6; anthers yellow-red; stigmas white, pubescent.
Seeds	somewhat thickened, not inflated.	thickened, not inflated.
Wood	hard.	hard.
Samaras	green to tan, elliptic to oval, ca. 0.75-1 cm, pubescent, margins ciliate, cilia ca. 0.5 mm.	light brown, ovoid to elliptic, 1-1.5 cm, narrowly winged, pubescent, margins densely ciliate, tip deeply notched.
2n	= 28.	= 28.

	Ulmus crassifolia	Ulmus serotina
Phenology	Flowering late summer–early fall.	Flowering late summer–fall.
Habitat	Stream banks, low woods, low hillsides, roadsides, waste places, sometimes shade trees	Limestone bluffs, stream sides, rich woods
Elevation	0-500 m (0-1600 ft)	0-400 m (0-1300 ft)
Distribution	AR; FL; LA; MS; OK; TN; TX; n Mexico [WildflowerSearch map] [BONAP county map]	AL; AR; GA; IL; MS; OK; TN; TX [WildflowerSearch map] [BONAP county map]
Discussion	Except for the Suwanee River valley in Florida, Ulmus crassifolia has not been found east of Webster County, Mississippi. It hybridizes with U. serotina. (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.)
Source	FNA vol. 3.	FNA vol. 3.
Parent taxa	Ulmaceae > Ulmus	Ulmaceae > Ulmus
Sibling taxa	U. alata, U. americana, U. glabra, U. parvifolia, U. procera, U. pumila, U. rubra, U. serotina, U. thomasii	U. alata, U. americana, U. crassifolia, U. glabra, U. parvifolia, U. procera, U. pumila, U. rubra, U. thomasii
Name authority	Nuttall: Trans. Amer. Philos. Soc., n.s. 5: 169. (1837)	Sargent: Bot. Gaz. 27: 92. (1899)
Web links	Local Web sites: LA Plants WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local Web sites: IL Wildflowers WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Ulmus serotina

cedar elm

red elm, september elm

Habit

Trees, 24-27 m; crowns rounded to narrow.

Trees, to 21 m; crowns spreading, broadly rounded.

Bark

light brown with shallow ridges and large plates.

light brown to reddish with shallow fissures.

Branches

often with opposite corky wings;

twigs reddish brown, pubescent.

spreading to pendulous, often developing irregular corky wings with maturity;

twigs brown to gray, pubescent to glabrous.

Buds

brown, apex acute, pubescent;

scales dark brown, shiny, glabrous.

brown, apex acute, glabrous;

scales dark brown, glabrous.

Leaves

blade ovate to elliptic, 2.5-5 × 1.3-2 cm, base oblique or rounded to cuneate, margins crenate to doubly serrate, apex obtuse;

surfaces abaxially softly pubescent, adaxially harshly pubescent.

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.

Inflorescences

fascicles, 2-5-flowered, 0.5 cm;

pedicel 0.75-1 cm.

racemes, 8-12-flowered, long, to 5 cm;

pedicel 0.5-1 cm.

Flowers

calyx deeply lobed, more than 1/2 its length, lobes 6-9, hairy;

stamens 5-6, anthers reddish purple;

stigmas white, pubescent, exserted and spreading.

calyx lobed almost to base, lobes 5-6;

stamens 5-6;

anthers yellow-red;

stigmas white, pubescent.

Seeds

somewhat thickened, not inflated.

thickened, not inflated.

Wood

hard.

Samaras

green to tan, elliptic to oval, ca. 0.75-1 cm, pubescent, margins ciliate, cilia ca. 0.5 mm.

light brown, ovoid to elliptic, 1-1.5 cm, narrowly winged, pubescent, margins densely ciliate, tip deeply notched.

= 28.

Ulmus serotina

Phenology

Flowering late summer–early fall.

Flowering late summer–fall.

Habitat

Stream banks, low woods, low hillsides, roadsides, waste places, sometimes shade trees

Limestone bluffs, stream sides, rich woods

Elevation

0-500 m (0-1600 ft)

0-400 m (0-1300 ft)

Distribution

AR; FL; LA; MS; OK; TN; TX; n Mexico

[WildflowerSearch map]

[BONAP county map]

AL; AR; GA; IL; MS; OK; TN; TX

[WildflowerSearch map]

[BONAP county map]

Discussion

Except for the Suwanee River valley in Florida, Ulmus crassifolia has not been found east of Webster County, Mississippi. It hybridizes with U. serotina.

(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.)

Source

FNA vol. 3.

Parent taxa

Ulmaceae > Ulmus

Sibling taxa

U. alata, U. americana, U. glabra, U. parvifolia, U. procera, U. pumila, U. rubra, U. serotina, U. thomasii

U. alata, U. americana, U. crassifolia, U. glabra, U. parvifolia, U. procera, U. pumila, U. rubra, U. thomasii

Name authority

Nuttall: Trans. Amer. Philos. Soc., n.s. 5: 169. (1837)

Sargent: Bot. Gaz. 27: 92. (1899)

Web links

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America

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Ulmus crassifolia

Ulmus serotina

Ulmus crassifolia

Ulmus serotina