Crataegus rivularis |
Crataegus ×fretalis |
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mountain river hawthorn, river hawthorn |
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Habit | Shrubs or trees, 30–50 dm. | Shrubs or trees, 60–70 dm. |
Stems | twigs: new growth greenish, sparsely pubescent, early glabrescent, 1–2-years old often red-purple; bark on younger 2–5 cm thick branches dark gray-brown, sometimes copper-colored; thorns on twigs straight or ± recurved, 2-years old black or purple-black, glossy, fine, 1.5–4 cm. |
trunk bark grayish to grayish brown, checked; twigs straight or slightly flexuous, new growth green, tinged red, at end of 1st year bright reddish brown, lustrous, 1–2-years old darker red-brown; thorns on twigs few, ± straight, 1-year old shiny red-brown, stout, 2–4 cm. |
Leaves | petiole 1–2.5 cm, glabrous; blade elliptic to narrowly elliptic, 3–8 cm, length 2+ times width, thin, base cuneate, lobes 0 or small apiculi at ends of some vein tips, margins serrate, teeth numerous, usually acute, fine to coarse, venation semicamptodromous, veins 4 or 5 per side, larger often branched proximal to ends, apex acute, abaxial surface glabrous, adaxial appressed-strigose young. |
deciduous; petiole slender, length 33–60% blade, glabrous, minutely red-glandular; blade yellow-green, ovate or oval, 5–8 × 4.5–7 cm, thin but firm, base rounded, lobes 3–5 per side, small, lobe apex acute to acuminate (or larger and sometimes with proximal lobes enlarged and deeply cleft), margins sharply serrate, venation craspedodromous, veins 4–6 per side, apex acute to acuminate, abaxial surface glabrous, adaxial short-appressed-pubescent young, glabrescent. |
Inflorescences | 6–12-flowered; branches glandular-punctate; bracteoles early caducous, usually present, margins sessile-glandular. |
5–12-flowered; branches glabrous; bracteoles caducous, linear, membranous, margins glandular. |
Flowers | 14–17 mm diam.; sepals broadly deltate, 6–8 mm, margins entire, apex narrow, glabrous; stamens 10, anthers pink, sometimes ivory; styles 3–5. |
20 mm diam.; hypanthium glabrous; sepals lanceolate, margins coarsely glandular-serrate; stamens 5, rarely 6–8, anthers red, small; styles 3. |
Pomes | deep red (mid Aug), black or blackish purple mature, suborbicular, 10 mm diam.; sepals ± erect to strongly outcurved or ± patent, 2–3 mm; pyrenes 3 or 4, sides eroded. |
bright red, oblong or obovate, 10–12 × 9–10 mm, glabrous; flesh slightly succulent; sepals often lost, ± erect, incurved; pyrenes 3, dorsally grooved, sides plane. |
Crataegus rivularis |
Crataegus ×fretalis |
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Phenology | Flowering mid May–early Jun; fruiting Aug–Sep. | Flowering May; fruiting Sep–Oct. |
Habitat | Intermontane streamsides, ditches, flood plains | Brush, open woods, rocky pastures |
Elevation | 1300–2300 m (4300–7500 ft) | 20–100 m (100–300 ft) |
Distribution |
AZ; CO; ID; NM; NV; UT; WY
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CT; MA; ME |
Discussion | Crataegus rivularis is most abundant in intermontane Colorado and Utah and is one of two hawthorns found in Arizona; it is rare in Nevada. There are reports from northwestern Texas (for example, D. S. Correll and M. C. Johnston 1970); they have not been verified. Crataegus rivularis is one of the more common woody species of mesic, valley bottom intermontane habitats. The species flowers early. Crataegus rivularis is superficially similar to the more or less sympatric, less common, C. saligna; it has larger leaves with fewer veins, larger flowers with ten stamens, and larger pomes. It differs from C. erythropoda little other than in leaf shape and ripe fruit color. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Crataegus ×fretalis is probably a hybrid between C. macrosperma and a species of ser. Coccineae. Crataegus tortilis Ashe from northern Illinois and Wisconsin is similar but has 20 stamens and usually five pyrenes. Crataegus vittata Ashe, from Pennsylvania, is also similar, but has truncate leaf bases. Crataegus knieskerniana Sargent is similar in foliage, flowers, and fruit, but it has pyrenes depressed or pitted on the inner faces and occurred near East Herkimer, New York. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 510. | FNA vol. 9, p. 638. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus |
Sibling taxa | ||
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) | Crataegus ×fretalis Sargent: Rhodora 5: 112. (1903) — as species |
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