Spiraea corymbosa
Spiraea virginiana
dwarf spiraea, shinyleaf meadowsweet
Virginia meadowsweet, Virginia or West Virginia spiraea, Virginia spiraea
erect to arching, branched.
erect to arching or prostrate, densely branched.
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 ovate to oblanceolate, 3–5 × 1–1.5 cm (length 3 times width), membranous, base acute, margins entire or dentate teeth 1–4 in distal 1/4 of blade, 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 to acuminate, abaxial surface glaucous, mostly glabrous, adaxial glabrous.
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, corymbiform or hemispheric panicles, 2–8 × 5–22 cm height 0.5–1 times diam.;
branches frequently in axils of leaves, usually glabrous or pubescent, sometimes villous.
1–3 mm, glabrous or glabrate.
1–3 mm, usually glabrous or pubescent, sometimes villous.
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.
5–7 mm diam.;
hypanthia turbinate to campanulate, 1.2–1.8 mm, surfaces glabrous or pubescent;
sepals triangular, 1–1.2 mm;
petals yellowish white, greenish white, or translucent white, ovate to orbiculate, 1.8–2 mm;
staminodes 0;
stamens 25–45, 2 times petal length.
nearly fusiform, 2–3 mm, shiny, glabrous.
oblanceoloid, 1.5–2 mm, shiny, glabrous.
= 36.
Spiraea corymbosa
Spiraea virginiana
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.)
Of conservation concern.
Spiraea virginiana is endemic to the southern Blue Ridge and Appalachian Plateau physiographic provinces. In stream and river reaches, where there is little variation in flow volume and velocity, available habitat for S. virginiana would decline over time without scour and redeposition of sediments. The species reproduces primarily through asexual propagation: the stems break during high flows, are transported and deposited in sediments, and take root, establishing plants (D. W. Ogle 1991b; C. M. Anders and Z. E. Murrell 2001). Ogle (1991, 1991b) conducted a comprehensive analysis of the species and found viable seed to be rare on individuals found within local populations, confined to a single stream corridor. When plants from different populations were brought together in cultivation, abundant viable seed was produced (Ogle 1991b).
All populations of Spiraea virginiana examined by J. R. Brzyski and T. M. Culley (2011) had higher levels of genetic differentiation among populations, and lower values of genotypic richness within populations, than would be expected for a clonal organism.
Spiraea virginiana is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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USDA Plants Database
