Crataegus rivularis |
Crataegus brittonii |
|
---|---|---|
mountain river hawthorn, river hawthorn |
Britton hawthorn |
|
Habit | Shrubs or trees, 30–50 dm. | Shrubs, slender, 30–40 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 pubescent, 1-year old gray-brown, ± shiny, glabrous, older gray; thorns on twigs often numerous, ± straight to slightly recurved, 1-year old blackish, ± slender, 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 3–6 mm, flared distally, pubescent, glandularity not recorded; blade elliptic-rhombic to broadly elliptic-rhombic, 2–3.5 cm (usually widest near middle), length/width = 1.3 or wider, base broadly cuneate, lobes 0, or 1(or 2) per side, margins crenate-serrate, teeth caducous, gland-tipped, venation ± craspedodromous, veins 3 or 4 per side, apex rounded to subacute, abaxial surface pale green, soft pubescent, indumentum variably persistent with age, adaxial dark green, appressed-pubescent. |
Inflorescences | 6–12-flowered; branches glandular-punctate; bracteoles early caducous, usually present, margins sessile-glandular. |
2–6-flowered; branches densely pubescent; bracteoles type 2. |
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. |
14–18 mm diam.; hypanthium densely pubescent; sepals foliaceous, at least as long as petals, adaxially pubescent; anthers ivory; styles 3–5. |
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. |
red or ruddy, sometimes becoming dull brown, 14 mm, pubescent; sepals reflexed; pyrenes 3–5. |
Crataegus rivularis |
Crataegus brittonii |
|
Phenology | Flowering mid May–early Jun; fruiting Aug–Sep. | Flowering Apr–May; fruiting Sep–Nov. |
Habitat | Intermontane streamsides, ditches, flood plains | Brush |
Elevation | 1300–2300 m (4300–7500 ft) | 0–200 m (0–700 ft) |
Distribution |
AZ; CO; ID; NM; NV; UT; WY
|
AL; GA; NC; TN |
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.) |
Of conservation concern. Crataegus brittonii is a rare species with a scattered distribution. For a discussion of the possibly synonymous but untypified pink-anthered Crataegus rhodella Ashe and C. arenicola Ashe see J. B. Phipps and K. A. Dvorsky (2006). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 510. | FNA vol. 9, p. 606. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Parvifoliae |
Sibling taxa | ||
Synonyms | C. uniflora var. brittonii | |
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) | Eggleston: Bull. Torrey Bot. Club 36: 640. (1909) |
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