Crataegus douglasii |
Crataegus sheridana |
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black hawthorn, Douglas' hawthorn |
Great Plains hawthorn |
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Habit | Shrubs, 40–80 dm. | Shrubs, 20–35 dm. |
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 color not recorded, pubescent, 1-year old light brown to olive-tan or mid brown, 2-years old dark gray or reddish brown overlaid dark gray, older gray; thorns on twigs usually numerous, usually recurved, 2-years old very dark, shiny red-brown, slender to moderately thick, (2.5–)3–5(–7) 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 40–50% blade, pubescent (especially in adaxial sulcus), ± densely sessile-glandular; blade sometimes broadly ovate or suborbiculate, sometimes ± ovate, elliptic-ovate to ovate, 3.5–5(–6) cm, nearly full grown at flowering, ± thin, base cuneate, broadly cuneate, or subtruncate to subcordate, lobes (3 or)4(or 5) per side, sinuses shallow, LII 5–15%, lobe apex acute (except where blades elliptic-ovate to ovate, then lobes deeper, LII 15–30%, lobe apex subacute), margins with subacute teeth, veins 3 or 4 per side, apex acute to obtuse, abaxial surface glabrous, veins glabrous or pubescent young, adaxial densely appressed-scabrous-pubescent young (variably persistent). |
Inflorescences | 10–25-flowered; branches glabrous; bracteole margins stipitate- or sessile-glandular. |
5–15-flowered; branches ± densely pubescent; bracteoles pallid, narrow, margins 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. |
14–16 mm diam.; hypanthium proximally ± tomentose, medially densely short-pubescent; sepals greenish, triangular, length not recorded, margins glandular-serrate, abaxially glabrous, adaxially pubescent; stamens 10, anthers ivory; styles 4 or 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. |
1–6 in infructescences, bright red, broadly ellipsoid to suborbicular, 9–11 mm tall, pubescent, rarely glabrate; sepals ± spreading to reflexed; pyrenes 3 or 4, sides ± roughened with shallow, irregular pitting or diagonal scarring. |
2n | = 68. |
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Crataegus douglasii |
Crataegus sheridana |
|
Phenology | Flowering May–Jun; fruiting Sep–Oct. | Flowering May–Jun; fruiting Sep. |
Habitat | Brush, old fields, fencerows, woodland edges | Thickets, brush |
Elevation | 50–1600 m (200–5200 ft) | 300–1200 m (1000–3900 ft) |
Distribution |
AK; CA; ID; MI; MN; MT; OR; WA; WI; AB; BC; ON; SK
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MN; MT; ND; SD; WY; 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 sheridana occurs only east of the Rocky Mountains and is abundant in the Cypress Hills of Alberta and Saskatchewan. Collections from the montane islands of Montana are also known. Until confusion with the superficially similar C. chrysocarpa of the Great Plains and Prairies is cleared up in all the relevant herbaria, we will have an incomplete knowledge of the distribution of C. sheridana; however, it is widespread in the Great Plains region. Its plants are usually taller than sympatric C. chrysocarpa and also C. macracantha. Crataegus sheridana has superficial resemblances to the C. chrysocarpa group; it is distinguished by its pitted pyrenes and usually larger leaves. In the Cypress Hills, where this species has the shortest thorns of any hawthorn in the red-fruited group, it is further distinguished from most specimens of the C. chrysocarpa group by the densely hairy to tomentose inflorescence branches and hypanthia and by its leaf shape. Collections from the Cypress Hills indicate that form of C. sheridana to be peculiarly round-leaved with pallid bracteoles; Montana forms have longer thorns, longer, more acutely lobed leaves, more elliptic-ovate to ovate blades, and red-brown rather than pallid bracteoles. In all likelihood, Crataegus sheridana represents a series of hybrid descendants between C. chrysocarpa and C. macracantha. The reasons for ignoring its existence over a long period were discussed by J. B. Phipps et al. (2007). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 512. | FNA vol. 9, p. 521. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Douglasianae | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Macracanthae > ser. Macracanthae |
Sibling taxa | ||
Synonyms | C. columbiana, C. tennowana | |
Name authority | Lindley: Edwards's Bot. Reg. 21: plate 1810. (1835) | A. Nelson: Bot. Gaz. 34: 370. (1902) |
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