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aubépine flabelliforme, fan-leaf hawthorn

mountain river hawthorn, river hawthorn

Habit Shrubs or trees, 40–50 dm. Shrubs or trees, 30–50 dm.
Stems

twigs: new growth reddish at first, usually sparsely pubescent, 1-year old deep chestnut brown, older dull gray;

thorns on twigs 1-year old shiny, dark brown, stout to slender, 4–6 cm.

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.

Leaves

petiole 1–2 mm wide, length 40–50% blade, glandular;

blade glossy, dark green, broadly elliptic to ovate, 4–7 cm, base cuneate to slightly rounded, lobes 4 or 5 per side, sinuses deep, lobe apex acuminate, margins sharply serrate, teeth gland-tipped, veins 5 or 6 per side, apex acute, abaxial surface glabrous except along veins, adaxial densely appressed-scabrous young, glabrescent.

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.

Inflorescences

5–10-flowered;

branches villous;

bracteole frequency not recorded, linear.

6–12-flowered;

branches glandular-punctate;

bracteoles early caducous, usually present, margins sessile-glandular.

Flowers

13–17 mm diam.;

hypanthium glabrous or villous at base;

sepals 4–5 mm, margins entire, glandular to glandular-serrate, rarely nearly eglandular, apex acute, abaxial pubescence not recorded;

stamens 5–10 or 20, anthers usually pink;

styles 3–5.

14–17 mm diam.;

sepals broadly deltate, 6–8 mm, margins entire, apex narrow, glabrous;

stamens 10, anthers pink, sometimes ivory;

styles 3–5.

Pomes

crimson, ± ellipsoid, 8–10 mm diam., sometimes ± pruinose;

sepals spreading or usually erose, not or obscurely elevated;

pyrenes 3–5, dorsally deeply grooved.

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.

2n

= 51.

Crataegus flabellata

Crataegus rivularis

Phenology Flowering May–Jun; fruiting Sep–Oct. Flowering mid May–early Jun; fruiting Aug–Sep.
Habitat Brush, successional fields, fencelines, woodland edges, open woodlands Intermontane streamsides, ditches, flood plains
Elevation 10–200 m (0–700 ft) 1300–2300 m (4300–7500 ft)
Distribution
from FNA
CT; MA; ME; NH; NY; VT; NB; NS; ON; QC
[WildflowerSearch map]
from FNA
AZ; CO; ID; NM; NV; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Crataegus flabellata occurs along the Niagara Escarpment in Ontario, on both sides of Lake Ontario and the St. Lawrence, to New Brunswick and Nova Scotia, and to Massachusetts. Reports for Newfoundland have not been substantiated.

Crataegus flabellata is distinctive with its leaf blades glossy dark green, ovate to broadly elliptic, cuneate at the base, and with deep acuminate lobes. Specimens with less glandularity or serration of the sepal margins may resemble C. fluviatilis. In spite of the obvious differences in morphology and range, C. flabellata and C. macrosperma often have been combined by floristicians. From C. chrysocarpa, C. flabellata is distinguished by its shinier, ellipsoid, glabrous fruit, by the usually deeper, acuminate lobes of its glossy, dark green leaves, and by longer, slightly more acute sepals. Typically, the inflorescences and hypanthia of eastern C. chrysocarpa are densely hairy, practically tomentose, unlike C. flabellata with its more sparsely hairy pedicels and glabrous distal hypanthia. It is conceivable that, due to morphological intermediacy and the sympatry of all three species within the range of C. flabellata, this species represents the result of ancient hybridization between C. chrysocarpa and C. macrosperma.

Crataegus flabellata is usually divided into two varieties: var. flabellata (10 stamens) and var. grayana (20 stamens), the latter being particularly common in southern Quebec. There appears to be little, if any, other constant differentiating feature. Crataegus crudelis, also from Quebec, is a form recognized by long thorns (to 10 cm).

The name Crataegus densiflora Sargent, which pertains to C. flabellata, is illegitimate.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

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.)

Source FNA vol. 9, p. 567. FNA vol. 9, p. 510.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Tenuifoliae Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones
Sibling taxa
C. aemula, C. aestivalis, C. alabamensis, C. alleghaniensis, C. annosa, C. aprica, C. aquacervensis, C. ashei, C. atrovirens, C. attrita, C. austromontana, C. beata, C. berberifolia, C. biltmoreana, C. brachyacantha, C. brainerdii, C. brazoria, C. brittonii, C. buckleyi, C. calpodendron, C. castlegarensis, C. chrysocarpa, C. coccinea, C. coccinioides, C. cognata, C. collina, C. colonica, C. communis, C. compacta, C. condigna, C. craytonii, C. crocea, C. crus-galli, C. cupressocollina, C. delawarensis, C. dispar, C. dodgei, C. douglasii, C. egens, C. egregia, C. enderbyensis, C. erythropoda, C. exilis, C. eximia, C. extraria, C. fecunda, C. flava, C. florens, C. floridana, C. florifera, C. fluviatilis, C. formosa, C. frugiferens, C. furtiva, C. gattingeri, C. gaylussacia, C. gilva, C. greggiana, C. harbisonii, C. holmesiana, C. ignava, C. incilis, C. integra, C. intricata, C. invicta, C. iracunda, C. irrasa, C. jesupii, C. jonesiae, C. lacrimata, C. laevigata, C. lanata, C. lancei, C. lanuginosa, C. lassa, C. laurentiana, C. leonensis, C. lepida, C. levis, C. lumaria, C. macracantha, C. macrosperma, C. magniflora, C. margarettae, C. marshallii, C. mendosa, C. meridiana, C. mira, C. mollis, C. monogyna, C. munda, C. nananixonii, C. neobushii, C. nitida, C. oakesiana, C. okanaganensis, C. okennonii, C. opaca, C. opima, C. orbicularis, C. ouachitensis, C. padifolia, C. pennsylvanica, C. persimilis, C. pexa, C. phaenopyrum, C. phippsii, C. pinetorum, C. populnea, C. prona, C. pruinosa, C. pulcherrima, C. punctata, C. purpurella, C. quaesita, C. reverchonii, C. rivularis, C. rivuloadamensis, C. rivulopugnensis, C. roribacca, C. rubella, C. rubribracteolata, C. saligna, C. sargentii, C. scabrida, C. schizophylla, C. schuettei, C. segnis, C. senta, C. sheila-phippsiae, C. sheridana, C. shuswapensis, C. sororia, C. spathulata, C. spes-aestatum, C. stolonifera, C. stonei, C. submollis, C. suborbiculata, C. succulenta, C. tecta, C. teres, C. texana, C. tracyi, C. triflora, C. turnerorum, C. uniflora, C. ursopedensis, C. venusta, C. viridis, C. visenda, C. wattiana, C. williamsii, C. wootoniana, C. ×atrorubens, C. ×bicknellii, C. ×coleae, C. ×collicola, C. ×disperma, C. ×dispessa, C. ×fretalis, C. ×incaedua, C. ×kelloggii, C. ×latebrosa, C. ×lucorum, C. ×rufula, C. ×sicca, C. ×vailiae
C. aemula, C. aestivalis, C. alabamensis, C. alleghaniensis, C. annosa, C. aprica, C. aquacervensis, C. ashei, C. atrovirens, C. attrita, C. austromontana, C. beata, C. berberifolia, C. biltmoreana, C. brachyacantha, C. brainerdii, C. brazoria, C. brittonii, C. buckleyi, C. calpodendron, C. castlegarensis, C. chrysocarpa, C. coccinea, C. coccinioides, C. cognata, C. collina, C. colonica, C. communis, C. compacta, C. condigna, C. craytonii, C. crocea, C. crus-galli, C. cupressocollina, C. delawarensis, C. dispar, C. dodgei, C. douglasii, C. egens, C. egregia, C. enderbyensis, C. erythropoda, C. exilis, C. eximia, C. extraria, C. fecunda, C. flabellata, C. flava, C. florens, C. floridana, C. florifera, C. fluviatilis, C. formosa, C. frugiferens, C. furtiva, C. gattingeri, C. gaylussacia, C. gilva, C. greggiana, C. harbisonii, C. holmesiana, C. ignava, C. incilis, C. integra, C. intricata, C. invicta, C. iracunda, C. irrasa, C. jesupii, C. jonesiae, C. lacrimata, C. laevigata, C. lanata, C. lancei, C. lanuginosa, C. lassa, C. laurentiana, C. leonensis, C. lepida, C. levis, C. lumaria, C. macracantha, C. macrosperma, C. magniflora, C. margarettae, C. marshallii, C. mendosa, C. meridiana, C. mira, C. mollis, C. monogyna, C. munda, C. nananixonii, C. neobushii, C. nitida, C. oakesiana, C. okanaganensis, C. okennonii, C. opaca, C. opima, C. orbicularis, C. ouachitensis, C. padifolia, C. pennsylvanica, C. persimilis, C. pexa, C. phaenopyrum, C. phippsii, C. pinetorum, C. populnea, C. prona, C. pruinosa, C. pulcherrima, C. punctata, C. purpurella, C. quaesita, C. reverchonii, C. rivuloadamensis, C. rivulopugnensis, C. roribacca, C. rubella, C. rubribracteolata, C. saligna, C. sargentii, C. scabrida, C. schizophylla, C. schuettei, C. segnis, C. senta, C. sheila-phippsiae, C. sheridana, C. shuswapensis, C. sororia, C. spathulata, C. spes-aestatum, C. stolonifera, C. stonei, C. submollis, C. suborbiculata, C. succulenta, C. tecta, C. teres, C. texana, C. tracyi, C. triflora, C. turnerorum, C. uniflora, C. ursopedensis, C. venusta, C. viridis, C. visenda, C. wattiana, C. williamsii, C. wootoniana, C. ×atrorubens, C. ×bicknellii, C. ×coleae, C. ×collicola, C. ×disperma, C. ×dispessa, C. ×fretalis, C. ×incaedua, C. ×kelloggii, C. ×latebrosa, C. ×lucorum, C. ×rufula, C. ×sicca, C. ×vailiae
Synonyms Mespilus flabellata, C. crudelis, C. flabellata var. densiflora, C. flabellata var. grayana, C. grayana
Name authority (Bosc ex Spach) K. Koch: Verh. Vereins Beförd. Gartenbaues Königl. Preuss. Staaten, ser. 2, 1: 240. (1853) Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840)
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