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low ninebark, mountain nine-bark

Habit Shrubs, 10 dm. Shrubs or trees, sometimes subshrubs or herbs.
Stems

often decumbent, spreading, reddish brown becoming dark gray, glabrous or sparsely stellate-hairy.

Leaves

stipules linear to narrowly elliptic or subulate, 4–5 × 1 mm, base attenuate, apex acute;

petiole 0.5–2.2 cm;

blade broadly ovate, 1.5–4 × 2–4.5 cm, sometimes wider than long, base usually truncate to cordate, rarely broadly cuneate, 0 or 1–5-lobed, margins doubly crenate to doubly serrate, apex rounded to obtuse, surfaces glabrous or sparsely stellate-hairy.

alternate, sometimes opposite, simple, sometimes pinnately compound;

stipules present or absent.

Inflorescences

10(–15)–30-flowered, fairly dense, hemispheric racemes, 4 cm diam.;

bracts linear to narrowly elliptic or narrowly obovate, 2–4 mm, apex acute, rarely 2-fid.

Pedicels

8–18 mm, sparsely to moderately stellate-hairy.

Flowers

8–10 mm diam.;

hypanthium cup-shaped, 1.7–2 mm, sparsely to moderately stellate-hairy;

sepals triangular to ovate, 3 mm, apex gland-tipped, surfaces sparsely to moderately stellate-hairy;

petals white, broadly elliptic to orbiculate, 4.5 × 4 mm;

stamens 20–40, ± equal to petals;

carpels (1)2(3), connate at least 1/2 their lengths, densely stellate-hairy.

torus absent or minute;

carpels 1–5(–8), distinct or +/- connate (Maleae), free or +/- adnate to hypanthium (many Maleae), styles distinct or +/- connate (some Maleae);

ovules (1 or)2(–5+), collateral, clustered, or biseriate.

Fruits

follicles aggregated or not, capsules, drupes aggregated or not, aggregated drupelets, pomes, or aggregated nutlets, rarely achenes or aggregated achenes;

styles persistent or deciduous, not elongate (elongate in Gillenieae).

Seeds

1–3, pyriform, 2–2.5 mm.

Follicles

(1)2(3), inflated, 2.5 mm (lengths shorter than sepals), densely stellate-hairy, hairs white;

styles 3.5 mm.

x

= 8, 9, 15, 17.

2n

= 18.

Physocarpus monogynus

Rosaceae subfam. amygdaloideae

Phenology Flowering May–Aug; fruiting Jul–Oct.
Habitat Open rocky wooded slopes, seepage ledges, canyons
Elevation 1800–2600 m (5900–8500 ft)
Distribution
from FNA
AZ; CO; MT; NM; NV; OK; SD; TX; UT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
HI; North America; Mexico; Central America; South America; Europe; Asia; Africa; Atlantic Islands (Madeira); Australia
Discussion

Cyanogenic glycosides are usually present in Amygdaloideae; sorbitol is present.

The name Amygdaloideae Arnott (1832) has priority over Spiraeoideae Arnott (1832), used by D. Potter et al. (2007), because Amygdalaceae (1820) is an earlier conserved name.

Tribes 9, genera 55, species ca. 1300 (9 tribes, 38 genera, 361 species, including 20 hybrids, in the flora)

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

Source FNA vol. 9, p. 350. FNA vol. 9, p. 345. Author: Luc Brouillet.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Neillieae > Physocarpus Rosaceae
Sibling taxa
P. alternans, P. capitatus, P. intermedius, P. malvaceus, P. opulifolius
Subordinate taxa
Synonyms Spiraea monogyna
Name authority (Torrey) J. M. Coulter: Contr. U.S. Natl. Herb. 2: 104. (1891) Arnott: Botany, 107. (1832)
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