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Washington hawthorn, Washington thorn

rufous mayhaw

Habit Trees, 40–100 dm. Shrubs or trees, 30–50 dm.
Stems

3-year old twigs shiny, deep reddish brown, older dark gray;

thorns on twigs ± straight, 2–5 cm.

twigs: new growth rusty-tomentose, 1-year old chestnut brown;

thorns on twigs 2-years old dark gray to black, 1–3(–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.

petiole length 10–15% blade;

blade elliptic to ovate, 2.5–4.5 cm, lobes 0 or sinuate (those on rapidly elongating shoots larger, usually proportionately wider than those on short shoots, sinuately lobed), margins entire or barely serrate or crenate in distal 1/3 or 1/2, teeth gland-tipped, veins 3–5 per side, apex subacute to obtuse, abaxial surface densely rufous-tomentose, especially on veins, adaxial densely white- or rufous-tomentose young, scabrous mature.

Inflorescences

15–30-flowered, flowers strong-smelling;

branches glabrous;

bracteole margins stipitate-glandular.

2–5-flowered umbels;

branches glabrous or rufous-tomentose;

bracteoles narrow, margins glandular.

Flowers

10–12 mm diam.;

hypanthium glabrous;

sepals 2 mm;

stamens 20, anthers ivory;

styles 3(or 4).

± precocious, 15–27.5 mm diam.;

hypanthium glabrous or rufous-tomentose;

sepal margins entire or slightly glandular-serrate;

petals 12 mm;

anthers red;

styles (4 or)5.

Pomes

red, 10 mm diam.;

sepals short-triangular;

pyrenes 5.

2n

= 51, 68.

= 34, 51.

Crataegus phaenopyrum

Crataegus ×rufula

Phenology Flowering Jun; fruiting Sep–Nov. Flowering Feb–Mar; fruiting May–Jun.
Habitat Woodland edges, gaps, scrub, damp locations Seasonally inundated depressions, ditches, sink holes, streamsides
Elevation 10–300 m (0–1000 ft) 10–100 m (0–300 ft)
Distribution
from FNA
AR; DE; FL; GA; IL; IN; KY; LA; MD; MI; MO; MS; NC; OH; OR; PA; SC; TN; VA; WA; WV; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA
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.)

Crataegus ×rufula is restricted to the Florida panhandle and adjacent Georgia and southeastern Alabama.

Crataegus ×rufula is a presumed hybrid between the other two mayhaws or descendants thereof (J. B. Phipps 1988b) as shown by morphometric analyses. Although in some characteristics (for example, the usually sinuate leaf margin) C. ×rufula is like C. opaca, it lacks the characteristic elongate leaves of the latter. Crataegus ×rufula also tends to intergrade with C. aestivalis, with which it is fully sympatric. The frequency of C. aestivalis-like intermediates could well be accounted for by pure C. aestivalis being reasonably common through the C. ×rufula range and C. opaca being scarce there. Some, not all, individuals of C. ×rufula have relatively large flowers. Crataegus ×rufula is locally common and conveniently treated as a species.

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

Source FNA vol. 9, p. 499. FNA vol. 9, p. 548.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Crataegus > ser. Cordatae Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Aestivales
Sibling taxa
C. aemula, C. aestivalis, C. alabamensis, C. alleghaniensis, C. annosa, C. aprica, C. aquacervensis, C. ashei, C. atrovirens, C. attrita, C. austromontana, C. beata, C. berberifolia, C. biltmoreana, C. brachyacantha, C. brainerdii, C. brazoria, C. brittonii, C. buckleyi, C. calpodendron, C. castlegarensis, C. chrysocarpa, C. coccinea, C. coccinioides, C. cognata, C. collina, C. colonica, C. communis, C. compacta, C. condigna, C. craytonii, C. crocea, C. crus-galli, C. cupressocollina, C. delawarensis, C. dispar, C. dodgei, C. douglasii, C. egens, C. egregia, C. enderbyensis, C. erythropoda, C. exilis, C. eximia, C. extraria, C. fecunda, C. flabellata, C. flava, C. florens, C. floridana, C. florifera, C. fluviatilis, C. formosa, C. frugiferens, C. furtiva, C. gattingeri, C. gaylussacia, C. gilva, C. greggiana, C. harbisonii, C. holmesiana, C. ignava, C. incilis, C. integra, C. intricata, C. invicta, C. iracunda, C. irrasa, C. jesupii, C. jonesiae, C. lacrimata, C. laevigata, C. lanata, C. lancei, C. lanuginosa, C. lassa, C. laurentiana, C. leonensis, C. lepida, C. levis, C. lumaria, C. macracantha, C. macrosperma, C. magniflora, C. margarettae, C. marshallii, C. mendosa, C. meridiana, C. mira, C. mollis, C. monogyna, C. munda, C. nananixonii, C. neobushii, C. nitida, C. oakesiana, C. okanaganensis, C. okennonii, C. opaca, C. opima, C. orbicularis, C. ouachitensis, C. padifolia, C. pennsylvanica, C. persimilis, C. pexa, C. phippsii, C. pinetorum, C. populnea, C. prona, C. pruinosa, C. pulcherrima, C. punctata, C. purpurella, C. quaesita, C. reverchonii, C. rivularis, C. rivuloadamensis, C. rivulopugnensis, C. roribacca, C. rubella, C. rubribracteolata, C. saligna, C. sargentii, C. scabrida, C. schizophylla, C. schuettei, C. segnis, C. senta, C. sheila-phippsiae, C. sheridana, C. shuswapensis, C. sororia, C. spathulata, C. spes-aestatum, C. stolonifera, C. stonei, C. submollis, C. suborbiculata, C. succulenta, C. tecta, C. teres, C. texana, C. tracyi, C. triflora, C. turnerorum, C. uniflora, C. ursopedensis, C. venusta, C. viridis, C. visenda, C. wattiana, C. williamsii, C. wootoniana, C. ×atrorubens, C. ×bicknellii, C. ×coleae, C. ×collicola, C. ×disperma, C. ×dispessa, C. ×fretalis, C. ×incaedua, C. ×kelloggii, C. ×latebrosa, C. ×lucorum, C. ×rufula, C. ×sicca, C. ×vailiae
C. aemula, C. aestivalis, C. alabamensis, C. alleghaniensis, C. annosa, C. aprica, C. aquacervensis, C. ashei, C. atrovirens, C. attrita, C. austromontana, C. beata, C. berberifolia, C. biltmoreana, C. brachyacantha, C. brainerdii, C. brazoria, C. brittonii, C. buckleyi, C. calpodendron, C. castlegarensis, C. chrysocarpa, C. coccinea, C. coccinioides, C. cognata, C. collina, C. colonica, C. communis, C. compacta, C. condigna, C. craytonii, C. crocea, C. crus-galli, C. cupressocollina, C. delawarensis, C. dispar, C. dodgei, C. douglasii, C. egens, C. egregia, C. enderbyensis, C. erythropoda, C. exilis, C. eximia, C. extraria, C. fecunda, C. flabellata, C. flava, C. florens, C. floridana, C. florifera, C. fluviatilis, C. formosa, C. frugiferens, C. furtiva, C. gattingeri, C. gaylussacia, C. gilva, C. greggiana, C. harbisonii, C. holmesiana, C. ignava, C. incilis, C. integra, C. intricata, C. invicta, C. iracunda, C. irrasa, C. jesupii, C. jonesiae, C. lacrimata, C. laevigata, C. lanata, C. lancei, C. lanuginosa, C. lassa, C. laurentiana, C. leonensis, C. lepida, C. levis, C. lumaria, C. macracantha, C. macrosperma, C. magniflora, C. margarettae, C. marshallii, C. mendosa, C. meridiana, C. mira, C. mollis, C. monogyna, C. munda, C. nananixonii, C. neobushii, C. nitida, C. oakesiana, C. okanaganensis, C. okennonii, C. opaca, C. opima, C. orbicularis, C. ouachitensis, C. padifolia, C. pennsylvanica, C. persimilis, C. pexa, C. phaenopyrum, C. phippsii, C. pinetorum, C. populnea, C. prona, C. pruinosa, C. pulcherrima, C. punctata, C. purpurella, C. quaesita, C. reverchonii, C. rivularis, C. rivuloadamensis, C. rivulopugnensis, C. roribacca, C. rubella, C. rubribracteolata, C. saligna, C. sargentii, C. scabrida, C. schizophylla, C. schuettei, C. segnis, C. senta, C. sheila-phippsiae, C. sheridana, C. shuswapensis, C. sororia, C. spathulata, C. spes-aestatum, C. stolonifera, C. stonei, C. submollis, C. suborbiculata, C. succulenta, C. tecta, C. teres, C. texana, C. tracyi, C. triflora, C. turnerorum, C. uniflora, C. ursopedensis, C. venusta, C. viridis, C. visenda, C. wattiana, C. williamsii, C. wootoniana, C. ×atrorubens, C. ×bicknellii, C. ×coleae, C. ×collicola, C. ×disperma, C. ×dispessa, C. ×fretalis, C. ×incaedua, C. ×kelloggii, C. ×latebrosa, C. ×lucorum, C. ×sicca, C. ×vailiae
Synonyms Mespilus phaenopyrum, C. youngii
Name authority (Linnaeus f.) Medikus: Gesch. Bot., 84. (1793) Crataegus ×rufula Sargent: J. Arnold Arbor. 1: 251. (1920)
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