Crataegus rivularis |
Crataegus ouachitensis |
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mountain river hawthorn, river hawthorn |
Ouachita hawthorn |
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Habit | Shrubs or trees, 30–50 dm. | Shrubs or trees, 40–60 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. |
twigs: new growth not recorded, 1-year old dark purplish, older gray; thorns on twigs ± straight, 2-years old dark purple, fine, 2–4 cm. |
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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. |
petiole very slender, 0.5 mm wide, length ca. equal to or 50–66% blade, sparsely hairy or glabrous, slightly glandular or eglandular; blade ovate to deltate-ovate, (2–)3–4 cm, thin, base broadly rounded to nearly truncate or subcordate, lobes 1–3 per side obscure, sinuses shallow, lobe apex subacute, margins sharply serrate nearly to base, veins 3 per side, apex acuminate, abaxial surface sparsely to ± densely hairy on veins, adaxial variable scabrous, glabrescent. |
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Inflorescences | 6–12-flowered; branches glandular-punctate; bracteoles early caducous, usually present, margins sessile-glandular. |
3–8-flowered; branches glabrous or sparsely villous; bracteoles not recorded. |
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Pedicels | glabrous or ± tomentose young. |
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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. |
15–18 mm diam.; hypanthium not seen; sepal length not recorded, margins glandular-serrate or subentire; stamens 20, anthers pink or rose to rose-purple; styles 3 or 4. |
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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. |
green until late, becoming bright red, obovoid to pyriform, 8–15 mm diam., glabrous; flesh hard; sepals on collar, strongly reflexed; pyrenes 3 or 4. |
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Crataegus rivularis |
Crataegus ouachitensis |
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Phenology | Flowering mid May–early Jun; fruiting Aug–Sep. | |||||
Habitat | Intermontane streamsides, ditches, flood plains | |||||
Elevation | 1300–2300 m (4300–7500 ft) | |||||
Distribution |
AZ; CO; ID; NM; NV; UT; WY
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AR |
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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.) |
Varieties 2. Crataegus ouachitensis is endemic to the Ouachita Mountains. Among ser. Intricatae, the species is distinct because of its small leaves, only slightly glandular nature, 20 stamens, and bright red pomes. The delicate leaves and pome color recall C. wootoniana (ser. Tenuifoliae). Crataegus ouachitensis is also similar to Louisianan 58. C. iracunda, differing primarily in having 20 stamens and conspicuously glandular-serrate sepal margins in the type form. Crataegus ouachitensis is very rare and likely of interserial hybrid origin, though it could also plausibly be referred to ser. Pulcherrimae. Crataegus thermopegea E. J. Palmer, from the same area, is perhaps related; it has laterally pitted pyrenes and probably ten stamens, according to Palmer. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 510. | FNA vol. 9, p. 591. | ||||
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Intricatae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) | E. J. Palmer: J. Arnold Arbor. 7: 124. (1926) | ||||
Web links |