Crataegus rivularis |
Crataegus ×latebrosa |
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mountain river hawthorn, river hawthorn |
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Habit | Shrubs or trees, 30–50 dm. | 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. |
trunks 15 cm diam.; compound thorns sometimes present on old trunks; branches spreading, forming wide flat or round-topped head; twigs: new growth with matted white hairs, later in 1st year becoming reddish brown, pubescent or puberulous, strongly flexuous, 1-year old gray, stout; thorns on twigs few or numerous, straight, 1-year old purple, slender, 2–7 cm, lustrous. |
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 20–37% blade, slightly winged apically, hoary tomentose early, glabrescent; blade dark yellow-green, ovate to oval, 5–8 × 3–6 cm, more than 1/2 grown at anthesis, base narrowly or broadly cuneate, lobes 0, margins coarsely doubly serrate, teeth straight, venation craspedodromous, midvein prominent, veins thin, conspicuous, apex acute or acuminate, rarely rounded, abaxial surface villous, adaxial densely villous glabrescent; leaves at end of vigorous extension shoots broadly ovate, often 9 × 7–8 cm, base broadly rounded or cuneate, lobes usually short, lobe apex broadly acuminate, margins more coarsely serrate, apex acuminate. |
Inflorescences | 6–12-flowered; branches glandular-punctate; bracteoles early caducous, usually present, margins sessile-glandular. |
5–10-flowered, compact; branches long-matted white-hairy; 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. |
20–25 mm diam.; hypanthium pubescent; sepals slender, margins minutely glandular-serrate, apex long-acuminate, abaxial surface slightly villous; stamens (5–)10, anthers rose; styles 3–5, base surrounded by wide ring of pale tomentum. |
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. |
on slender, drooping, pubescent pedicels, orange-red, suborbicular, 10 mm diam., hairy; flesh yellow, thin, soft; sepals prominent, with short tube, spreading or closely appressed; pyrenes 3–5, 5–6 mm, base rounded, apex narrowed and rounded, dorsally slightly grooved, sides plane. |
Crataegus rivularis |
Crataegus ×latebrosa |
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Phenology | Flowering mid May–early Jun; fruiting Aug–Sep. | Flowering Apr; fruiting Sep–Oct. |
Habitat | Intermontane streamsides, ditches, flood plains | Brush, open woods, rocky pastures |
Elevation | 1300–2300 m (4300–7500 ft) | 100–200 m (300–700 ft) |
Distribution |
AZ; CO; ID; NM; NV; UT; WY
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AR; MO |
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 ×latebrosa differs little from C. ×dispessa except in the lower stamen number (5–10) and wider range of style number (3–5). The only record of fruit color says orange-red; reports for C. ×dispessa uniformly declare crimson. The very narrow, caducous bracteoles and the leaf shape of C. ×latebrosa suggest a C. collina × ser. Molles ancestry. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 510. | FNA vol. 9, p. 639. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus |
Sibling taxa | ||
Synonyms | C. noelensis | |
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) | Crataegus ×latebrosa Sargent: Rep. (Annual) Missouri Bot. Gard. 22: 73. (1912) — as species |
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