Flora of North America species comparison

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Crataegus rivularis

Crataegus submollis

mountain river hawthorn, river hawthorn

aubépine subsoyeuse, northern downy hawthorn, northern red haw, Quebec hawthorn
Habit Shrubs or trees, 30–50 dm. Shrubs, sometimes 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.

twigs: new growth appressed-pubescent, 1-year old tan to brown, older gray;

thorns on twigs usually numerous, straight to curved, 2-years old shiny blackish, ± thick, 4–7 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, densely pubescent, ± glandular, glands black;

blade ± broadly ovate to rhombic-elliptic, 4–9(–11) cm, chartaceous, base cuneate to almost truncate, lobes 3–5 per side, obscure on smaller leaves, sinuses shallow to moderately deep, lobe apex acuminate, margins sharply, doubly serrate, on larger leaves teeth 2–3 mm, gland-tipped at least initially, veins 5–7 per side, apex acute to subobtuse, abaxial surface sparsely appressed-pubescent, sometimes glabrescent, veins abaxially pubescent, adaxial densely scabrous-pubescent young, variably glabrescent.
Inflorescences

6–12-flowered;

branches glandular-punctate;

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

5–15-flowered;

branches densely pubescent;

bracteoles caducous, linear, membranous, margins sessile-glandular, larger similar but late-deciduous, more herbaceous.
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.

20–22 mm diam.;

hypanthium tomentose;

sepals narrowly triangular, 6–7 mm, margins deeply glandular-serrate, abaxially pubescent;

stamens 10(or 20), 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.

bright red, suborbicular to pyriform or ellipsoid, 10–15 mm diam., hairy, especially proximally and distally;

sepals prominent, erect-patent, stiff;

pyrenes 3–5.
2n

= 68.

Crataegus rivularis

Crataegus submollis
Phenology Flowering mid May–early Jun; fruiting Aug–Sep. Flowering May–Jun; fruiting Sep–Oct.
Habitat Intermontane streamsides, ditches, flood plains Brush, natural hedgerows, field margins, apparently calciphile
Elevation 1300–2300 m (4300–7500 ft) 20–400 m (100–1300 ft)
Distribution
from FNA
AZ; CO; ID; NM; NV; UT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
MA; ME; MI; NH; NY; OH; PA; VT; WI; NB; NS; ON; QC [Introduced in Europe]
[WildflowerSearch map]
[BONAP county map]
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 submollis ranges from eastern Wisconsin and northern Michigan through the limestone areas of southern Ontario into Quebec, and New York to Maine and southern Nova Scotia. It is occasionally found in Pennsylvania and is plausible for northern West Virginia. It is allopatric with C. mollis. Crataegus submollis has also been recorded wild in Europe, including France and northern Italy.

Crataegus submollis, though quite similar to C. mollis, differs in its distribution, stature, petiole glandularity, stamen number, and greater thorniness.

The typical form of Crataegus submollis has proportionately broader leaves that are broadly cuneate to subcordate basally. By contrast, C. champlainensis is a form with proportionately narrower leaves more or less truncate to subcordate at the base. Intermediate forms are common in Quebec and New England. Placing the 20-stamen C. canadensis, a distinctive local form from the Montreal area, with C. submollis is based on leaf shape, glandular petioles, and disjunction from the range of C. mollis. Crataegus arnoldiana is a form with particularly large fruit.

Possession of glandular petioles and similar flowering time means that Crataegus submollis can sometimes show surprising similarity to large specimens of C. chrysocarpa. Then, the large fruiting calyces and the tendency to a more herbaceous larger bracteole type of C. submollis, typical for ser. Molles, differentiate.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 9, p. 510. FNA vol. 9, p. 556.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Molles
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. 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
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. 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. 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 C. arnoldiana, C. canadensis, C. champlainensis
Name authority Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) Sargent: Bot. Gaz. 31: 7. (1901)
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Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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