Crataegus rivularis |
Crataegus meridiana |
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mountain river hawthorn, river hawthorn |
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Habit | Shrubs or trees, 30–50 dm. | Shrubs or trees, 30–70 dm, branches ± weeping. |
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 appressed-pubescent, 1-year old gray-brown to blackish gray, slender to relatively stout; thorns on twigs absent or frequent, ± straight, 1-year old purple-brown, becoming gray, slender, 2–3.5 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. |
petiole length 30–50% blade, persistently pubescent, glandular; blade narrowly to broadly cuneate to obtrullate, 2–4 cm (1/3 smaller young), thin, becoming floppy, lobes 1–3 per side, subterminal, sinuses shallow, lobe apex obtuse to acute, margins glandular crenate-serrate, veins 2 or 3 per side, apex rounded to subacute, surfaces pubescent, glabrescent adaxially, abaxial veins densely tomentose. |
Inflorescences | 6–12-flowered; branches glandular-punctate; bracteoles early caducous, usually present, margins sessile-glandular. |
2–4-flowered; branches appressed-canescent; bracteoles linear, 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. |
18–20 mm diam.; hypanthium densely canescent; sepals narrowly triangular, 4–6 mm, margins glandular-serrate, abaxially pubescent; anthers ivory; styles 2–4(or 5). |
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. |
orange-yellow to ruddy, suborbicular, 9–12 mm diam., pubescent; sepals on collar, reflexed; pyrenes 2–4(or 5). |
Crataegus rivularis |
Crataegus meridiana |
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Phenology | Flowering mid May–early Jun; fruiting Aug–Sep. | Flowering Mar–Apr; fruiting Jul–Aug. |
Habitat | Intermontane streamsides, ditches, flood plains | Brush, open woodlands |
Elevation | 1300–2300 m (4300–7500 ft) | 0–200 m (0–700 ft) |
Distribution |
AZ; CO; ID; NM; NV; UT; WY
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AL; FL; GA; SC |
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 meridiana is a poorly understood complex of forms with long-petiolate, terminally lobed, more or less narrowly obtrullate leaves, with similarities to C. quaesita and C. senta. The general form of the leaf is similar to that of C. quaesita but is more shortly and obscurely lobed than in C. senta. Unlike C. quaesita, extension-shoot leaves are more likely to be more or less isodiametric. More delicate specimens of C. meridiana might key to C. floridana, but the fruit is larger. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 510. | FNA vol. 9, p. 631. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Lacrimatae |
Sibling taxa | ||
Synonyms | C. tristis | |
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) | Beadle: Biltmore Bot. Stud. 1: 115. (1902) |
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