Crataegus douglasii |
Crataegus suborbiculata |
|
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black hawthorn, Douglas' hawthorn |
caughuawaga hawthorn |
|
Habit | Shrubs, 40–80 dm. | Shrubs or trees, 80 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 reddish, 1-year old tan, 2-years old light gray; thorns on twigs straight, 2-years old blackish, usually shiny, ± slender, 2.5–4.5 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 50–100% blade, eglandular or with 1–2(–3) glands; blade broadly elliptic or rhombic to suborbiculate, 4–6 cm, thin, base cuneate to broadly cuneate, lobes 3 or 4 per side, sinuses shallow, lobe apex acute, margins serrate, eglandular, veins 5 or 6 per side, apex acute to obtuse, surfaces glabrous, adaxial sparsely hairy young. |
Inflorescences | 10–25-flowered; branches glabrous; bracteole margins stipitate- or sessile-glandular. |
5–10-flowered; branches glabrous; bracteoles sometimes absent, margins 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. |
20–24 mm diam.; sepals narrowly triangular, 5–6 mm, margins subentire, abaxially glabrous; stamens 20, anthers cream, pink, or red, 0.7 mm; styles 4. |
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. |
pink mauve, ripening to orange-red or purplish, 10–14 mm diam., pruinose at first; sepals not on collar, spreading; pyrenes 3 or 4. |
2n | = 68. |
= 68. |
Crataegus douglasii |
Crataegus suborbiculata |
|
Phenology | Flowering May–Jun; fruiting Sep–Oct. | Flowering May–Jun; fruiting Sep–Oct. |
Habitat | Brush, old fields, fencerows, woodland edges | Woodland margins, brush |
Elevation | 50–1600 m (200–5200 ft) | 50–300 m (200–1000 ft) |
Distribution |
AK; CA; ID; MI; MN; MT; OR; WA; WI; AB; BC; ON; SK
|
CT; MI; NY; ON; QC |
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.) |
Of conservation concern. Crataegus suborbiculata is uncommon but is found in a number of locations in southern Ontario, and extends east to Quebec, New York, and Connecticut, and west to Michigan. Fruiting specimens, seemingly of this species but in poor condition, have been collected along the Skyline Drive of Virginia. Very rare forms with slight inflorescence pilosity may occur and then Crataegus suborbiculata may look very much like some forms of C. florifera (ser. Anomalae), which is distinguished by its pyrenes. One large Ontario population is rather similar to C. compacta except that it is larger in all its parts and has proportionately slightly wider leaves. Very rare forms with narrower leaves (elliptic-rhombic) and small anthers may be referred to C. nitidula Sargent, known from southern Ontario, Michigan, Pennsylvania, and Wisconsin. Forms named C. umbratilis Sargent from Connecticut and Pennsylvania have slightly larger, more venous leaves with larger marginal teeth than the above and an elevated calyx in fruit. The poorly understood C. durobrivensis Sargent was suggested by E. J. Palmer (1952) to be a hybrid with C. pruinosa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 512. | FNA vol. 9, p. 574. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Douglasianae | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Pruinosae |
Sibling taxa | ||
Synonyms | C. columbiana, C. tennowana | |
Name authority | Lindley: Edwards's Bot. Reg. 21: plate 1810. (1835) | Sargent: Rhodora 3: 72. (1901) |
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