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cluster rose, cluster wild rose, peafruit rose, swamp rose

acicular rose, arctic rose, bristly rose, prickly rose, prickly wild rose

Habit Shrubs, loosely clustered or in dense thickets. Shrubs, forming dense thickets.
Stems

ascending to erect, (2–)4–20(–25) dm, openly branched;

bark ± glaucous when young, dark reddish brown or dull red with age outer layer may exfoliate as thin ash gray peel, glabrous;

infrastipular prickles usually paired, erect, rarely curved, usually subulate, 2–10 × 2–4 mm, base glabrous, internodal prickles rare or absent.

erect, stout, (3–)10–20(–25) dm, sparsely or densely branched distally;

bark pale brown with tips dull red, glabrous;

infrastipular prickles absent, internodal prickles dense, erect, subulate, terete, ± flattened, 9 × 4 mm, sparsely stipitate-glandular, mixed with dense aciculi.

Leaves

5–10(–13) cm;

stipules 8–22 × 2–5 mm, auricles flared, 2–5 mm, margins usually entire, sometimes erose or lobed, finely ciliolate to ciliate, eglandular, surfaces glabrous or sparsely pubescent, sparsely stipitate-glandular or eglandular;

petiole and rachis sometimes with pricklets, glabrous or hairy hairs to 1 mm, sometimes stipitate-glandular;

leaflets 5–7(–9), terminal: petiolule 8–12 mm, blade elliptic-ovate, (15–)20–45(–60) × 9–16(–20) mm, widest at or below middle, membranous, base cuneate to obtuse, margins 1(–2)-serrate, teeth 12–22 per side, on distal 3/4–4/5 of margin, acute, eglandular, apex acute, sometimes obtuse, abaxial surfaces pale green, usually sparsely pubescent, eglandular, adaxial green, dull, glabrous, rarely puberulent.

5.5–15 cm;

stipules 20–25 × 3–8 mm, auricles flared or erect, 5–7 mm, margins usually entire, stipitate-glandular, surfaces glabrous, sometimes puberulent, sparsely sessile-glandular or eglandular;

petiole and rachis usually (rarely) with pricklets, glabrous or puberulent to pubescent, sessile-glandular;

leaflets 5–7 (on annual shoots), terminal: petiolule 6–20 mm, blade elliptic, ovoid, or ovate-lanceolate, 20–60 × 13–32 mm, firm, margins 1(–2+)-dentate-serrate, teeth 11–25 per side acute or obtuse, gland-tipped or eglandular, apex acute or obtuse, abaxial surfaces light green, glabrous or puberulent (on main veins), eglandular or sparsely to densely sessile-glandular, adaxial green, dull, glabrous or sparsely hairy.

Inflorescences

corymbs, sometimes panicles or solitary flowers, 1–12-flowered.

corymbs, 1 or 2(or 3)-flowered.

Pedicels

erect, sometimes recurved, slender, 10–22 mm, usually glabrous, sometimes finely puberulent, eglandular, rarely stipulate-glandular;

bracts 2–3, lanceolate, 8–14 × 3–6 mm, margins entire, sometimes serrate, irregularly stipitate-glandular and/or erose, surfaces glabrous or pubescent, eglandular.

reflexed as hips mature, slender, (13–)20–28(–35) mm, glabrous, stipitate-glandular or eglandular;

bracts 1–3, ovoid, 18–22 × 4–14 mm, margins entire, sessile- or short stipitate-glandular, surfaces glabrous, sometimes hairy, eglandular.

Flowers

2.4–3.8 cm diam.;

hypanthium ovoid-urceolate, 3–5 × 2.5–3.5 mm, glabrous, rarely setose, eglandular, neck (0–)0.5–1 × 2 mm;

sepals spreading, ovate-lanceolate, 10–17 × 1.5–3 mm, tip 3–7(–10) × 1.5–2.5 mm, margins entire, abaxial surfaces sometimes puberulent, densely or sparsely stipitate-glandular, rarely eglandular;

petals single, pink to deep pink, 12–18 × 10–18 mm;

stamens 75;

carpels 22–35, styles exsert 1–2 mm beyond stylar orifice (1 mm diam.) of hypanthial disc (3.5 mm diam.).

3–6 cm diam.;

hypanthium ovoid to oblong, 5–8 × 4–6 mm, glabrous, eglandular, neck 1 × 2.5–3 mm;

sepals spreading, often beak-capped, lanceolate, 20–33 × (2.5–)3–3.5 mm, tip 7–12 × 0.5–0.8 mm, margins entire, sometimes pinnatifid, abaxial surfaces glabrous, sometimes pubescent, eglandular or stipitate-glandular (north);

petals single, rose pink to pale pink, (13–)22–25 × (11–)20–25 mm;

stamens 75–100;

carpels 18–33, styles exsert 1 mm beyond stylar orifice (2 mm diam.) of ± flat hypanthial disc (3.5–4.5 mm diam.).

Hips

scarlet, globose, sometimes subglobose or ovoid, 7–15 × 7–13 mm, fleshy, glabrous, eglandular, rarely setose- or stipitate-glandular, neck (0–)1–1.5 × 1.5–3.5 mm;

sepals persistent, erect.

orange-red to bright red or blue-purple, globose to ellipsoid or urceolate, 10–23 × 9–11 mm, fleshy, glabrous, eglandular, neck 1–2 × 2–2.5 mm;

sepals persistent, erect, often beak-capped.

Achenes

basiparietal, 5–35, tan, 3–4 × 1.5–2.5 mm.

basiparietal, 14–25, tan, 4 × 2–2.5 mm.

2n

= 14, 28.

Rosa pisocarpa

Rosa acicularis

Distribution
from FNA
CA; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CO; IA; MA; ME; MI; MN; MT; ND; NH; NY; SD; VT; WI; WV; WY; AB; BC; MB; NB; NS; NT; NU; ON; QC; SK; YT; Eurasia
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

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

Subspecies 2 (2 in the flora).

Rosa acicularis is circumpolar in forests of Eurasia and North America. Octoploid subsp. acicularis occurs from Sweden across northern Russia to Outer Mongolia, northern China, Korea, and Japan; hexaploid subsp. sayi is found throughout northern North America. The two subspecies meet in an intergradation zone from eastern Siberia to Alaska, and perhaps Yukon (W. H. Lewis 1958), where ploidy level is required for subspecies or hybrid confirmation.

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

Key
1. Inflorescences (1–)3–12-flowered; sepal abaxial surfaces usually stipitate-glandular, tips to 10 mm; infrastipular prickles (1–)2; hips usually globose, rarely subglobose, abruptly narrowed to necks 1.5–3 mm diam.; leaflets most commonly 7, terminal blade 15–35 mm.
subsp. pisocarpa
1. Inflorescences 1–3(–10+)-flowered; sepal abaxial surfaces usually eglandular, rarely stipitate-glandular, tips to 7 mm; infrastipular prickles 0–1(–2); hips subglobose to ovoid, gradually to abruptly narrowed to necks 2.5–3.5 mm diam.; leaflets most commonly 5, terminal blade 20–45(–60) mm.
subsp. ahartii
1. Pedicels densely stipitate-glandular; leaflets 5 (or 7), margins 1(–2+)-dentate-serrate; sepal abaxial surfaces usually stipitate-glandular.
subsp. acicularis
1. Pedicels usually eglandular, if stipitate-glandular, not to apex or stipitate glands mostly sparse; leaflets 5–7, margins 1–2-dentate-serrate; sepal abaxial surfaces usually eglandular.
subsp. sayi
Source FNA vol. 9, p. 109. FNA vol. 9, p. 114.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Roseae > Rosa > subg. Rosa > sect. Rosa Rosaceae > subfam. Rosoideae > tribe Roseae > Rosa > subg. Rosa > sect. Rosa
Sibling taxa
R. acicularis, R. arkansana, R. blanda, R. bracteata, R. bridgesii, R. californica, R. canina, R. carolina, R. cinnamomea, R. foliolosa, R. gallica, R. glauca, R. gymnocarpa, R. laevigata, R. lucieae, R. minutifolia, R. mollis, R. multiflora, R. nitida, R. nutkana, R. palustris, R. pinetorum, R. rubiginosa, R. rugosa, R. setigera, R. sherardii, R. spinosissima, R. spithamea, R. stellata, R. tomentosa, R. virginiana, R. woodsii
R. arkansana, R. blanda, R. bracteata, R. bridgesii, R. californica, R. canina, R. carolina, R. cinnamomea, R. foliolosa, R. gallica, R. glauca, R. gymnocarpa, R. laevigata, R. lucieae, R. minutifolia, R. mollis, R. multiflora, R. nitida, R. nutkana, R. palustris, R. pinetorum, R. pisocarpa, R. rubiginosa, R. rugosa, R. setigera, R. sherardii, R. spinosissima, R. spithamea, R. stellata, R. tomentosa, R. virginiana, R. woodsii
Subordinate taxa
R. pisocarpa subsp. ahartii, R. pisocarpa subsp. pisocarpa
R. acicularis subsp. acicularis, R. acicularis subsp. sayi
Name authority A. Gray: Proc. Amer. Acad. Arts 8: 382. (1872) Lindley: Ros. Monogr., 44, plate 8. (1820)
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