Crataegus douglasii |
Crataegus rivuloadamensis |
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black hawthorn, Douglas' hawthorn |
Adams Creek hawthorn |
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Habit | Shrubs, 40–80 dm. | Shrubs or trees, 25–40(–50) dm, wide-branching. |
Stems | 1-year old twigs deep tan to dark mahogany, ± shiny young, older gray to dark gray, often showing brown or alternatively tan-brown eastward; thorns on twigs straight or slightly recurved, deep brown young, (1.5–)2–3.5 cm. |
twigs: new growth dark reddish green, pubescent, 1-year old shiny, dark red-brown, 2-years old dark reddish and gray; thorns on twigs ± straight, 1-year old glossy, very dark red-brown, older dark gray, shorter conic, stout, 1.5–2.5(–3) cm. |
Leaves | petiole 0.7–1.5 cm, pubescent young, slightly glandular; blade usually elliptic to broadly elliptic or subrhombic (elliptic-obovate when lobes very small), 4–7 cm, lobes 2–4 per side, sinuses shallow, LII 10–20%, lobe apex subobtuse to acute, margins coarsely, sharply serrate, teeth small, gland-tipped young, venation craspedodromous, veins 4 or 5 per side, apex acute to obtuse, abaxial surface usually glabrous except on veins, adaxial densely short-appressed-pubescent. |
petiole length 25–35% blade, eglandular or sparsely sessile-glandular, stipitate-glandular at leaf base, adaxial sulcus densely pubescent; blade ± elliptic or broadly elliptic to rhombic-elliptic, 2–4 cm at anthesis, 4–8 cm mature, base cuneate to narrowly cuneate, lobes 2–4 per side, max LII (0–)5–20(–25)%, lobe apex subacute to broadly cuspidate, margins finely crenate-serrate or serrate, veins 4–6 per side, hardly impressed, apex acute, abaxial surface glabrous or sparsely hairy young, veins appressed-scabrous, adaxial ± densely appressed-scabrous (indumentum persisting). |
Inflorescences | 10–25-flowered; branches glabrous; bracteole margins stipitate- or sessile-glandular. |
4–10-flowered; branches ± densely tomentose; bracteoles ± reddish, narrow, margins densely sessile-glandular. |
Flowers | 10–15 mm diam.; hypanthium glabrous; sepals broadly triangular, 3–4 mm, margins sparsely glandular, adaxially glabrous; stamens 10, anthers pink; styles 3 or 4. |
17–21 mm diam.; hypanthium densely pubescent except sometimes distally; sepal color not recorded, broadly triangular, 3 mm, margins greenish, abaxial surface glabrous, adaxial pubescent; petals pale cream; anthers pink; styles 3–5. |
Pomes | vinous and usually waxy glaucous young, dull black mature, usually ellipsoid, 6–8 mm diam., glabrous; sepal remnants reflexed, apex obtuse; pyrenes 3 or 4, sides excavated, sometimes only shallowly. |
1–5(–6) per infructescence, pale reddish purple, becoming deep red to reddish plum and burgundy, suborbicular to broadly turbinate, 10–12 mm, usually ± densely hairy; sepals ± patent to recurved, 4–5 mm; pyrenes 3–5, dorsally strongly grooved, sides plane to very shallowly concave. |
2n | = 68. |
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Crataegus douglasii |
Crataegus rivuloadamensis |
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Phenology | Flowering May–Jun; fruiting Sep–Oct. | Flowering late May–early Jun; fruiting Aug–Sep. |
Habitat | Brush, old fields, fencerows, woodland edges | Thickets, under light shade of aspen |
Elevation | 50–1600 m (200–5200 ft) | 800–1200 m (2600–3900 ft) |
Distribution |
AK; CA; ID; MI; MN; MT; OR; WA; WI; AB; BC; ON; SK
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AB; SK |
Discussion | Crataegus douglasii occurs from southern and western British Columbia to the panhandle of Alaska and ranges to northern California and the Rocky Mountains of Idaho, Montana, and southwestern Alberta. Disjunct populations occur farther east in the Cypress Hills (Alberta and Saskatchewan), the Montana montane islands, and around the northern Great Lakes. In western North America, C. douglasii is found mainly near water in drier areas; in more mesic regions, it may occur in open woodlands. In the Great Lakes area, it mainly occurs in old pastures and on fencerows. Crataegus douglasii is distinguished from C. gaylussacia by having ten stamens and is rather variable in leaf shape and size. The species is distinguished from C. okennonii by the latter usually being taller and typically more erect as well as having a usually straight, single trunk, shorter thorns, ampulliform-orbicular fruit, and often purplish crimson fall foliage. Crataegus castlegarensis is the most similar species, and beyond possessing relatively few to many multiple thorns, it is distinguished from C. douglasii by its hairy hypanthia, pedicels, and, often, fruit, which is orbicular, plump, crimson to purple in late August, ripening to deep purple (sometimes black) at a time when sympatric C. douglasii is fully black. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Crataegus rivuloadamensis is known only from the western half of the Cypress Hills and is most abundant at elevations above 1150 m. The extremely dark young wood and short and conic thorns show strong resemblance to species of the Eurasian sect. Sanguineae Zabel ex C. K. Schneider. The unpitted pyrenes are a marked difference. The petals appear to be pale cream rather than pure white. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 512. | FNA vol. 9, p. 634. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Douglasianae | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Unassigned > ser. Montaninsulae |
Sibling taxa | ||
Synonyms | C. columbiana, C. tennowana | |
Name authority | Lindley: Edwards's Bot. Reg. 21: plate 1810. (1835) | J. B. Phipps & O’Kennon: J. Bot. Res. Inst. Texas 1: 1065, plate 7.3a, fig. 13. (2007) |
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