Spiraea corymbosa |
Spiraea |
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dwarf spiraea, shinyleaf meadowsweet |
meadowsweet, spiraea, spirea, spirée |
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Habit | Shrubs, 3–10(–15) dm. | Shrubs, 1–40 dm; usually rhizomatous. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | erect to arching, branched. |
5–20+, usually erect to ascending or arching, sometimes spreading, prostrate, or decumbent; bark reddish to dark brown, gray, or gray-black, exfoliating or not; long and short shoots present; young stems tan or reddish brown to brown, glabrous or villous. |
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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. |
deciduous (tardily so in S. thunbergii, partly persistent in S. cantoniensis), cauline, alternate, dimorphic with shoot type, simple; petiole present; blade obovate to oblanceolate, rhombic, elliptic, or linear to lanceolate, ovate, or suborbiculate, 1–10 cm, membranous, chartaceous, or coriaceous, margins flat, serrate to serrulate, dentate, or entire, venation pinnate, surfaces glabrous or hairy. |
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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 or mostly axillary, (2–)3–1000+-flowered, panicles or corymbiform or racemiform, hairy or glabrous; bracts present or absent; bracteoles present or absent. |
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Pedicels | 1–3 mm, glabrous or glabrate. |
present. |
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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. |
opening before or after full foliation, 2–15 mm diam.; epicalyx bractlets 1 or 2; hypanthium usually hemispheric or campanulate, sometimes turbinate or crateriform, 0.5–2(–5) mm, ± densely hairy or glabrous; sepals 5, usually erect, spreading, or reflexed, sometimes ascending, deltate, triangular, ovate-triangular, or ovate; petals 5, greenish, yellowish, chalky, or translucent white, white, pink [rose], or purple, ovate to obovate, suborbiculate, or orbiculate, sometimes elliptic; staminodes present or reduced to annulus, nectariferous; stamens 10–50 in 2–4 series, shorter or longer than petals; torus absent or reduced; carpels [3 or]4 or 5[–8], free, glabrate to tomentose, styles terminal or subterminal, stigmas capitate or discoid; ovules 2[–4]. |
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Fruits | aggregated follicles, 4 or 5, cymbiform, ellipsoid, falcate, fusiform, or oblanceoloid, (0.5–)1.5–4 mm, coriaceous, glabrous or tomentose; hypanthium persistent; sepals persistent or deciduous, spreading, ascending, erect, or reflexed; styles persistent or deciduous. |
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Seeds | 2–4 per follicle, fusiform to oblong, 2–4 mm. |
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Follicles | nearly fusiform, 2–3 mm, shiny, glabrous. |
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x | = 9. |
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2n | = 36. |
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Spiraea corymbosa |
Spiraea |
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Phenology | Flowering May–Oct; fruiting Jun–Nov. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Open rocky soil, rocky, lightly wooded sites, dry or fast draining slopes, rocky edges of woods | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 0–500 m (0–1600 ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
GA; MA; MD; NC; NJ; PA; TN; VA; WV; NS; ON [Introduced in e Europe] |
North America; Europe; Asia [Introduced widely, especially in the northern hemisphere, where often cultivated] |
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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.) |
Species 100–120 (17, including 3 hybrids, in the flora). Spiraea has been a popular decorative plant in North America, Europe, and Asia. Horticultural hybrids have been named. Hybridization also occurs in natural settings, complicating the identification of the species and varieties. For specimens that are suspected of being naturalized or of hybrid origin, additional references for identification include horticultural works such as L. H. Bailey et al. (1949), W. J. Bean (1970–1988, vol. 4), A. J. Rehder (1927), H. S. Maxwell and S. G. Knees (1989), and A. Huxley et al. (1992, vol. 4), or the major floristic treatments by A. I. Pojarkova (1971) and Lu L. T. and C. Alexander (2003), and references therein. The position of Spiraea within the Rosaceae has been the subject of considerable speculation; treatments by D. Potter et al. (2002, 2007b) are particularly useful. The floral ontogeny and morphology of S. alba and S. trilobata Linnaeus were examined and compared to other members of the Amygdaloideae by R. C. Evans and T. A. Dickinson (1999b). Spiraea hypericifolia Linnaeus has been found naturalized in eastern Texas (J. N. Mink et al. 2011) and has been reported in Mississippi (plants.usda.gov). The species is native to central and southwestern Asia and southeastern Europe; it has been widely cultivated in Europe and North America, but there are few reports of its escape and naturalization. The invasive potential of S. hypericifolia is uncertain and will likely vary with local site conditions. In its native habitat, it can form thickets on dry slopes and in riparian zones and wet meadows. A description of Spiraea hypericifolia follows: Shrubs 5–15 dm, usually rhizomatous. Stems erect to ascending. Leaves: petiole 1–4 mm; blade oblong-obovate or obovate lanceolate, 1.5–2 × 0.3–0.8 cm, length 2–4 times width, base acute, margins entire or with a few reduced teeth at apex, apex acute to obtuse, surfaces usually glabrous. Inflorescences axillary, 4–12-flowered, 0.75–2.5 × 1–3 cm. Flowers 5–8 mm diam.; hypanthia campanulate, 2–4 mm; sepals triangular, 1.5–2 mm; petals white, obovate to suborbiculate, 3–4 mm; staminodes 10–12; stamens 16–22, 0.8 times petal length. Follicles oblanceoloid, 1.4–2 mm, glabrous. In North America, Spiraea hypericifolia would most resemble S. prunifolia or S. thunbergii and can be distinguished from these two species in that they have a leaf blade margin that is sharply serrulate, whereas in S. hypericifolia the margin is entire or with only a few teeth at the apex. Other characters that are helpful are leaf shape; see the descriptions of 12. S. prunifolia and 13. S. thunbergii for comparative details. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 403. | FNA vol. 9, p. 398. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Spiraeeae > Spiraea | Rosaceae > subfam. Amygdaloideae > tribe Spiraeeae | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | S. betulifolia var. corymbosa, S. ostryfolia, S. repens, S. sororia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Rafinesque: Précis Découv. Somiol., 36. (1814) | Linnaeus: Sp. Pl. 1: 489. (1753): Gen. Pl. ed. 5, 216. (1754) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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