Flora of North America species comparison

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Crataegus phaenopyrum

Crataegus collina

Washington hawthorn, Washington thorn

hillside hawthorn
Habit Trees, 40–100 dm. Shrubs, 60–80 dm.
Stems

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

thorns on twigs ± straight, 2–5 cm.

twigs: new growth pubescent, 1–2-years old grayish brown, older gray;

thorns on twigs few to numerous, ± straight, 1-year old dark gray, usually ± slender, 2–4 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 1 cm, length 10–20% blade, unwinged part often short or absent, pubescent, eglandular;

blade rhombic-obovate or broadly elliptic, sometimes ± narrowly obovate, ± obtrullate, or broadly rhombic-elliptic, 3–5(–7.5) cm, 1.4–2.5 times as long as wide, base tapering into petioles, lobes 0, or 1 or 2(or 3) per side, lobe apex acute to subacute, rarely obtuse, margins serrate in distal 3/4, veins 5–7 per side, apex subacute to obtuse, abaxial surface scabrous-pubescent, especially on veins, adaxial scabrous-pubescent young, glabrescent.
Inflorescences

15–30-flowered, flowers strong-smelling;

branches glabrous;

bracteole margins stipitate-glandular.

5–10-flowered;

branches appressed-pubescent;

bracteoles membranous, margins sessile- or short-stipitate-glandular; flowering usually early, often before full leaf expansion.
Flowers

10–12 mm diam.;

hypanthium glabrous;

sepals 2 mm;

stamens 20, anthers ivory;

styles 3(or 4).

(10–)13–18(–20) mm diam.;

hypanthium glabrous or ± sparsely pubescent;

sepal margins usually glandular-serrate, abaxially glabrous;

stamens (5–)20, anthers white, cream, or rose;

styles (3–)5.
Pomes

orange or ruddy to deep red, orbicular, 8–14 mm diam., punctate, usually glabrous;

sepals patent-reflexed;

pyrenes (3–)5.
2n

= 51, 68.

= 34, 51, 68.

Crataegus phaenopyrum

Crataegus collina
Phenology Flowering Jun; fruiting Sep–Nov.
Habitat Woodland edges, gaps, scrub, damp locations
Elevation 10–300 m (0–1000 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; AR; GA; IL; IN; KS; KY; LA; MO; MS; NC; SC; TN; VA
[WildflowerSearch map]
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.)

Varieties 5 (5 in the flora).

Crataegus collina is found from Oklahoma and Kansas to the Atlantic. It is absent from middle and higher elevations in the Appalachians, where it is replaced by C. punctata.

Crataegus collina is similar to its almost allopatric counterpart C. punctata, differing in its less tabulate growth habit, leaves on extension shoots not deeply incised, fewer-flowered inflorescences, fewer (5–7 vs. 7–10) and less impressed veins, often wider leaf shape (especially in var. hirtiflora), somewhat darker twig color, sepal margins more or less glandular-serrate, and sometimes different stamen number. Crataegus collina is one of the first hawthorns to flower in its area of distribution, unlike C. punctata, which is late mid season. Crataegus ×disperma (see Interserial Hybrids) is somewhat similar to C. collina; it is allopatric and usually has more lateral leaf veins and fewer pyrenes. Crataegus collina is apparently intolerant of drought and is often leafless by late August in dry summers.

Crataegus collina is variable and has been divided into varieties. The varieties have been worked out in Missouri but not systematically recorded elsewhere; the varietal distributions provided here may be incomplete. Three putative hybrids between C. collina or C. punctata (C. ×collicola, C. ×disperma, and C. ×incaedua) are included in the following key.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Styles and pyrenes 2 or 3; stamens 10–15; leaves: adaxial surfaces sparsely hairy or subglabrous young
→ 2
1. Styles and pyrenes (3–)5; stamens (5–)15–20; leaves: adaxial surfaces short-pubescent, puberulent, or pubescent young (except var. sordida and C. ×collicola)
→ 3
2. Inflorescence branches glabrous; anthers pink or red-purple.
C. ×disperma
2. Inflorescence branches puberulent; anthers cream.
C. ×incaedua
3. Leaf blades 2/3 to nearly full grown at anthesis, length/width = 1.3, lobes, if present, usually obtuse
→ 4
3. Leaf blades usually 1/3–1/2 full grown at anthesis, length/width = 1.4–2.25+, lobes, if present, usually acute
→ 5
4. Stamens 15–20; leaf blades 3–5 cm, lobes 0 or obscure.
var. hirtiflora
4. Stamens 5–15(–20); leaf blades 5–7.5 cm, lobes 1 or 2 per side.
var. lettermanii
5. Anthers white or cream
→ 6
5. Anthers rose
→ 7
6. Leaf blades at anthesis: length/width = 1.4–1.7; flowers 14–18 mm diam.
var. collina
6. Leaf blades at anthesis: length/width = 1.75–2.25; flowers 10–12 mm diam
var. succincta
7. Leaf blades at anthesis: length/width = 1.75–2.25.
var. succincta
7. Leaf blades at anthesis: length/width = 1.4–1.5
→ 8
8. Leaf margins serrate distally, teeth 1.5 mm.
var. sordida
8. Leaf margins serrulate, teeth 0.5–0.7 mm.
C. ×collicola
Source FNA vol. 9, p. 499. FNA vol. 9, p. 543.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Crataegus > ser. Cordatae Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Punctatae
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. 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. ×rufula, C. ×sicca, C. ×vailiae
Subordinate taxa
C. collina var. collina, C. collina var. hirtiflora, C. collina var. lettermanii, C. collina var. sordida, C. collina var. succincta, C. ×collicola, C. ×disperma, C. ×incaedua
Synonyms Mespilus phaenopyrum, C. youngii
Name authority (Linnaeus f.) Medikus: Gesch. Bot., 84. (1793) Chapman: Fl. S.E. U.S. ed. 2 repr. 2, 684. (1892)
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).



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