Spiraea corymbosa |
Spiraea ×hitchcockii |
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dwarf spiraea, shinyleaf meadowsweet |
Hitchcock's spiraea, spirea |
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Habit | Shrubs, 3–10(–15) dm. | Shrubs, 10–12 dm. |
Stems | erect to arching, branched. |
erect to arching, or decumbent, 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. |
petiole 2–5 mm; blade narrowly elliptic to elliptic, obovate, 2–5(–6) × 1–2.8 cm, membranous, base acute to obtuse, margins irregularly serrulate to irregularly erose, venation pinnate, simple craspedodromous or semicraspedodromous, secondary veins prominent, apex usually obtuse, sometimes acute, abaxial surface puberulent, adaxial glabrescent. |
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 terminal, irregularly shaped, usually elongate-conic to elongate-pyriform panicles, 1.5–6(–9) × 1.5–3(–4.5) cm height 0.5–1(–2) times diam.; branches puberulent. |
Pedicels | 1–3 mm, glabrous or glabrate. |
2–5 mm, puberulent. |
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. |
3–8 mm diam.; hypanthia crateriform, 0.7–1.1 mm, abaxial surface puberulent, adaxial puberulent; sepals deltate, 0.5–1 mm; petals pink to dark pink, elliptic to wide elliptic, 1.3–1.7 mm; staminodes 5–12; stamens 10–20, 1–2 times petal length. |
Follicles | nearly fusiform, 2–3 mm, shiny, glabrous. |
asymmetrically falcate, 0.8–1.3 mm, not shiny, glabrous. |
2n | = 36. |
= 54. |
Spiraea corymbosa |
Spiraea ×hitchcockii |
|
Phenology | Flowering May–Oct; fruiting Jun–Nov. | Flowering Jun–Sep; fruiting Jul–Nov. |
Habitat | Open rocky soil, rocky, lightly wooded sites, dry or fast draining slopes, rocky edges of woods | Wet meadows, aspen meadows, lake margins, moist woodland margins, wetlands, along creeks |
Elevation | 0–500 m (0–1600 ft) | 300–2000 m (1000–6600 ft) |
Distribution |
GA; MA; MD; NC; NJ; PA; TN; VA; WV; NS; ON [Introduced in e Europe] |
OR
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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.) |
Hess and Stoynoff described Spiraea ×hitchcockii as a naturally occurring hybrid of S. douglasii var. menziesii and S. splendens var. rosea; it has been found within the Cascades of Oregon and is very likely to be found in other areas of the Pacific Northwest, where the two species have overlapping ranges. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 403. | FNA vol. 9, p. 406. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Spiraeeae > Spiraea | Rosaceae > subfam. Amygdaloideae > tribe Spiraeeae > Spiraea |
Sibling taxa | ||
Synonyms | S. betulifolia var. corymbosa, S. ostryfolia, S. repens, S. sororia | |
Name authority | Rafinesque: Précis Découv. Somiol., 36. (1814) | Spiraea ×hitchcockii W. J. Hess & Stoynoff: Sida 18: 827. (1999) |
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