Spiraea corymbosa
Précis Découv. Somiol., 36. 1814.
Shrubs, 3–10 (–15) dm. Stems erect to 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. 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. Pedicels 1–3 mm, glabrous or glabrate. 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. Follicles nearly fusiform, 2–3 mm, shiny, glabrous. 2n = 36.
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
Distribution
N.S., Ont., Ga., Md., Mass., N.J., N.C., Pa., Tenn., Va., W.Va., in e Europe
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.
Selected References
None.
Lower Taxa
"dm" is not declared as a valid unit of measurement for this property.