Crataegus phaenopyrum

(Linnaeus f.) Medikus

Gesch. Bot., 84. 1793.

Common names: Washington thorn
Endemic
Basionym: Mespilus phaenopyrum Linnaeus f. Suppl. Pl., 254. 1782
Synonyms: Crataegus youngii Sargent
Treatment appears in FNA Volume 9. Treatment on page 499.

Trees, 40–100 dm. Stems: 3-year old twigs shiny, deep reddish-brown, older dark gray; thorns on twigs ± straight, 2–5 cm. Leaves: petiole slender, sometimes both abaxially and adaxially short rusty-tomentose, eglandular; blade broadly to narrowly deltate, 3–6 cm, base truncate to rarely cuneate or cordate, sometimes very shallowly so, lobes palmately or pinnately 2 (or 3) per side, margins serrulate, veins 6 or 7 (or 8) per side (to sinuses), apex acute, surfaces glabrous. Inflorescences 15–30-flowered, flowers strong-smelling; branches glabrous; bracteole margins stipitate-glandular. Flowers 10–12 mm diam.; hypanthium glabrous; sepals 2 mm; stamens 20, anthers ivory; styles 3 (or 4). 2n = 51, 68.


Phenology: Flowering Jun; fruiting Sep–Nov.
Habitat: Woodland edges, gaps, scrub, damp locations
Elevation: 10–300 m

Distribution

V9 838-distribution-map.jpg

Ont., Ark., Del., Fla., Ga., Ill., Ind., Ky., La., Md., Mich., Miss., Mo., N.C., Ohio, Oreg., Pa., S.C., Tenn., Va., Wash., W.Va.

Discussion

Crataegus phaenopyrum has a wide native range across the middle latitudes of the United States from Missouri to Maryland and southward but is not particularly abundant. In the northern and western states and Ontario, it is introduced. All alleged specimens for Alabama proved to be wrongly identified (J. B. Phipps 1998).

The flowering season of the Washington thorn is the latest of all North American hawthorns. The species is one of the most widely planted ornamentals in the genus, being elegantly treelike and possessing beautiful, remarkably rust-resistant foliage at all seasons as well as attractive flowers and fruit. Several cultivars are known.

Crataegus cordata (Miller) Aiton 1789 (= Mespilus cordata Miller 1757) was commonly used for C. phaenopyrum until the early 20th century (J. B. Phipps 1999).

Selected References

None.

Lower Taxa

None.
... more about "Crataegus phaenopyrum"
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
James B. Phipps +
(Linnaeus f.) Medikus +
exfoliating +
compound +  and simple +
opposite +  and alternate +
truncate +  and rarely cuneate or cordate +
Mespilus phaenopyrum +
8 cm80 mm <br />0.08 m <br /> (12 cm120 mm <br />0.12 m <br />) +
bronze and purple +
deltate +
3 cm30 mm <br />0.03 m <br /> (6 cm60 mm <br />0.06 m <br />) +
stipitate-glandular +
adnate +  and distinct +
crowded +, scattered +  and alternate +
Washington thorn +
Ont. +, Ark. +, Del. +, Fla. +, Ga. +, Ill. +, Ind. +, Ky. +, La. +, Md. +, Mich. +, Miss. +, Mo. +, N.C. +, Ohio +, Oreg. +, Pa. +, S.C. +, Tenn. +, Va. +, Wash. +  and W.Va. +
not +  and aggregated +
10–300 m +
1 cm10 mm <br />0.01 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
strong-smelling +
unisexual +  and bisexual +
not +  and aggregated +
not +  and aggregated +
yellow +  and red or purplish +
0.6 cm6 mm <br />0.006 m <br /> (2 cm20 mm <br />0.02 m <br />) +
tomentose +  and glabrous +
Woodland edges, gaps, scrub, damp locations +
constricted +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
crassinucellate +
deciduous +
stipitate-glandular +
serrate +  and crenate +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and basal +
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
elliptic +  and circular +
0 (?) +  and 4 (?) +
free +  and distinct +
post-mature +
rusty-tomentose +
Flowering Jun +  and fruiting Sep–Nov. +
adnate +, free +, connate +  and distinct +
dark gray-brown +  and russet +
exfoliating +  and corrugated +
vermillion +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
orbicular +
Gesch. Bot., +
not arillate +
persistent +
free +  and distinct +
appressed +  and erect +
deciduous +  and persistent +
triangular +
2 cm20 mm <br />0.02 m <br /> (?) +
1-50-flowered +  and few-leaved +
craspedodromous +
free +  and distinct +
branched +  and simple +
elongate +
persistent +
distinct +
exsert +  and lateral +
elongate +
Crataegus youngii +
Crataegus phaenopyrum +
Crataegus (sect. Crataegus) ser. Cordatae +
species +
6 cm60 mm <br />0.06 m <br /> (10 cm100 mm <br />0.1 m <br />) +
curved +  and straight +
slender +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
craspedodromous +  and gland-tipped +
inconspicuous +
1 +  and few +
dark gray +  and reddish-brown +
straight +
determinate +
older +  and old +
7 +  and 6 +