Crataegus phaenopyrum |
Crataegus harbisonii |
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Washington hawthorn, Washington thorn |
Harbison hawthorn, Harbison's hawthorn |
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Habit | Trees, 40–100 dm. | Shrubs or trees, 50–80 dm. |
Stems | 3-year old twigs shiny, deep reddish brown, older dark gray; thorns on twigs ± straight, 2–5 cm. |
twigs: new growth sparsely pilose, 1-year old chestnut brown, becoming smooth; thorns on twigs frequent, 2-years old glossy, dark brown or nearly black, stout, 3–4 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. |
petiole length 15–20% blade, sparsely pilose, gland-dotted; blade shiny green, broadly elliptic to ovate, 4–7 cm, base cuneate, lobes 0 or 1–4 per side, sometimes apiculi, sinuses very shallow, margins doubly serrate, 5 teeth per cm, teeth 2 mm, gland-tipped early, veins 6 or 7 per side, apex acute, abaxial surface pubescent on veins mature, adaxial appressed-pubescent young. |
Inflorescences | 15–30-flowered, flowers strong-smelling; branches glabrous; bracteole margins stipitate-glandular. |
5–12-flowered, arising subterminally from perennial short shoots, also frequently on leafy side shoots of season lateral to extension shoots; branches pilose; bracteoles semipersistent, ligulate, 7–18 mm, subherbaceous, margins glandular-pectinate to glandular-serrate. |
Flowers | 10–12 mm diam.; hypanthium glabrous; sepals 2 mm; stamens 20, anthers ivory; styles 3(or 4). |
20–25 mm diam.; hypanthium pubescent; sepals lanceolate, margins glandular-laciniate; stamens 20, anthers cream to light yellow; styles 3–5. |
Pomes | orange-red to red, 12–22 mm diam., pubescent; sepals patent-reflexed; pyrenes 3–5. |
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2n | = 51, 68. |
= 68. |
Crataegus phaenopyrum |
Crataegus harbisonii |
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Phenology | Flowering Jun; fruiting Sep–Nov. | Flowering early May; fruiting Sep–Nov. |
Habitat | Woodland edges, gaps, scrub, damp locations | Wooded hills, creekside brush |
Elevation | 10–300 m (0–1000 ft) | 0–200 m (0–700 ft) |
Distribution |
AR; DE; FL; GA; IL; IN; KY; LA; MD; MI; MO; MS; NC; OH; OR; PA; SC; TN; VA; WA; WV; ON
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AL; TN |
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). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Crataegus harbisonii is rare and is similar both to C. ashei and C. triflora and could perhaps be thought of as a particularly robust form of C. ashei; however, it is perhaps more likely of hybrid origin between these species. The most significant similarity to C. triflora (ser. Triflorae) is an ability to produce inflorescences on shoots of the season lateral to extension shoots. Nevertheless, it is easily distinguished from C. triflora by characteristics of growth habit, by its smaller flowers (except in the Louisiana and some Mississippi forms of C. triflora) with fewer stamens, by the more coriaceous leaves with larger and more distant teeth, by having among the most persistent bracteoles in the genus, a feature that led to the creation of ser. Bracteatae. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 499. | FNA vol. 9, p. 608. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Crataegus > ser. Cordatae | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Bracteatae |
Sibling taxa | ||
Synonyms | Mespilus phaenopyrum, C. youngii | SELECTEDREFERENCE |
Name authority | (Linnaeus f.) Medikus: Gesch. Bot., 84. (1793) | Beadle: Bot. Gaz. 28: 413. (1899) |
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