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dwarf spiraea, shinyleaf meadowsweet

Reeve's spiraea or meadowsweet, Reeves' meadowsweet

Habit Shrubs, 3–10(–15) dm. Shrubs, 3–20 dm, not rhizomatous.
Stems

erect to arching, branched.

arching, branched.

Leaves

petiole 3–8 mm, sparsely hairy;

blade ovate to elliptic or suborbiculate, 2–10 × 1–2.5 cm, coriaceous, base obtuse, rounded, or subcordate, margins irregularly, coarsely and sharply doubly serrate from midpoint to apex, teeth acute and mucronate, number of primary and secondary serrations 1 times number of secondary veins (excluding inter-secondary veins), venation pinnate cladodromous, secondary veins not prominent, apex acute, obtuse, or rounded, abaxial surface mostly glabrous, adaxial glabrous.

sometimes partly persistent;

petiole 3–10 mm;

blade rhombic-lanceolate, 2–7 × 0.5–2 cm, membranous to chartaceous, base cuneate to obtuse, margins coarsely serrate or irregularly 3-fid to slightly lobed distally, venation pinnate simple craspedodromous, secondary veins not prominent, apex acute, abaxial surface blue-green, glaucous, glabrous, adaxial dark green, glabrous.

Inflorescences

mostly terminal, corymbiform, 2–5 × 3–10 cm height 0.4–1.1 times diam.;

branches rarely in axils of leaves, glabrous or glabrate.

mostly axillary, corymbiform or hemispheric panicles, 2–5 × 2–5 cm;

filiform bractlets sometimes present at base;

branches glabrous or pubescent.

Pedicels

1–3 mm, glabrous or glabrate.

10–20 mm, glabrous or pubescent.

Flowers

4–7 mm diam.;

hypanthia hemispheric, 0.8–1 mm, abaxial surface glabrous or pubescent, adaxial glabrous;

sepals triangular, 0.5–1 mm;

petals chalky white to pink, orbiculate, 1.3–1.5 mm;

staminodes 5–15 reduced to serrations;

stamens 15–20, 2 times petal length.

often double-flowered, usually distinct, 10–15 mm diam.;

hypanthia campanulate to turbinate, 3–5 mm, abaxial surface glabrous or sparsely hairy, adaxial glabrous;

sepals deltate, 1–1.5 mm;

petals white, elliptic to orbiculate, 2–4 mm;

staminodes 10–12;

stamens 20–28, 0.5–1 times petal length.

Follicles

nearly fusiform, 2–3 mm, shiny, glabrous.

inflated cymbiform, 0.5–2 mm, glabrous.

2n

= 36.

Spiraea corymbosa

Spiraea cantoniensis

Phenology Flowering May–Oct; fruiting Jun–Nov. Flowering May–Jun; fruiting Jun–Sep.
Habitat Open rocky soil, rocky, lightly wooded sites, dry or fast draining slopes, rocky edges of woods Meadows, woodland edges, abandoned homesteads
Elevation 0–500 m (0–1600 ft) 0–300 m (0–1000 ft)
Distribution
from FNA
GA; MA; MD; NC; NJ; PA; TN; VA; WV; NS; ON [Introduced in e Europe]
from FNA
AL; AR; LA; NC; NY; OH; VA; Asia (China) [Introduced in North America; introduced also in Mexico, Central America (Costa Rica, Panama), South America (Bolivia, Brazil, Colombia, Ecuador), s Africa, Pacific Islands (New Zealand), Australia]
[BONAP county map]
Discussion

H. A. Gleason and A. Cronquist (1963) and L. J. Uttal (1974) considered Spiraea corymbosa to be a variety of S. betulifolia. K. Sax (1936) found S. corymbosa to be a triploid with complete pollen sterility and hypothesized that it must exist as a diploid, or form viable egg cells, because it is involved in hybrids. If so, these cytological differences may be correlated with some morphological variation.

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

Spiraea cantoniensis as found in China has a five-petaled flower, as is typical of the genus; the native species is rarely found or cultivated in North America. Instead, a cultivar (lanceata, flore pleno) with twice or more the number of petals, frequently referred to as “double-flowered,” is the representative of S. cantoniensis most commonly established in the flora area; it does not appear to be invasive. Other references that may be helpful in identifying this taxon include L. H. Bailey et al. (1949), H. S. Maxwell and S. G. Knees (1989), A. Huxley et al. (1992, vol. 4), and Lu L. T. and C. Alexander (2003).

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

Source FNA vol. 9, p. 403. FNA vol. 9, p. 409.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Spiraeeae > Spiraea Rosaceae > subfam. Amygdaloideae > tribe Spiraeeae > Spiraea
Sibling taxa
S. alba, S. cantoniensis, S. chamaedryfolia, S. douglasii, S. japonica, S. lucida, S. prunifolia, S. salicifolia, S. splendens, S. stevenii, S. thunbergii, S. tomentosa, S. virginiana, S. ×hitchcockii, S. ×pyramidata, S. ×vanhouttei
S. alba, S. chamaedryfolia, S. corymbosa, S. douglasii, S. japonica, S. lucida, S. prunifolia, S. salicifolia, S. splendens, S. stevenii, S. thunbergii, S. tomentosa, S. virginiana, S. ×hitchcockii, S. ×pyramidata, S. ×vanhouttei
Synonyms S. betulifolia var. corymbosa, S. ostryfolia, S. repens, S. sororia
Name authority Rafinesque: Précis Découv. Somiol., 36. (1814) Loureiro: Fl. Cochinch. 1: 322. (1790)
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