9. Lysimachia vulgaris L. (garden loosestrife)

Map 2329

Plants with usually elongate, relatively stout, stoloniferous rhizomes. Stems 30–90 cm long, relatively stout (3–6 mm in diameter at the base), erect or strongly ascending, not rooting at the nodes, unbranched or occasionally with 1 or few branches toward the tip, not developing bulbils in the leaf axils, moderately to densely pubescent with short, spreading to somewhat crinkly, multicellular hairs, especially around the nodes, usually somewhat sticky to the touch, often also with faint, scattered, glandular dots and lines. Lower stem leaves usually shed by flowering, sometimes reduced to small, sessile, ovate, scales grading into the main leaves in the lower 1/3 of the stem. Main stem leaves opposite, or some of them in whorls of 3, sessile to very short-petiolate (petiole to 4 mm). Main leaf blades 5–12 cm long, 1–4 cm wide, lanceolate to narrowly ovate or elliptic-ovate, angled or occasionally more or less rounded at the base, angled or tapered to a sharply pointed tip, the margins entire or slightly wavy, flat, the surfaces with faint orangish red gland dots or punctations, the upper surface green to dark green, sparsely to moderately pubescent with minute, glandular hairs, the undersurface lighter green, with moderate, short, crinkly, multicellular hairs, especially along the veins, also with minute, glandular hairs; secondary veins evident. Inflorescences terminal and from the upper leaf axils, racemes and the axillary ones usually small panicles of loose clusters, the inflorescences relatively short-stalked (1–4 cm), the individual flower stalks 0.3–1.5 cm long, hairy (some of the hairs minute and glandular). Calyces (4)5(6)-lobed, the lobes 3–5 mm long, lanceolate, the margins with a reddish purple to nearly black line or band, usually with a very narrow thin, pale area just outside of this and finely glandular-hairy, the surface usually lacking evident gland-dots or lines, with a somewhat thickened and keeled midvein, this usually hairy. Corollas (4)5(6)-lobed, the lobes 8–12 mm long, obovate to broadly elliptic, rounded to bluntly pointed at the tip, the margins entire, yellow, densely pubescent with minute, yellow, more or less spherical glands on the upper surface and usually reddish-tinged or with reddish markings on the upper surface toward the base, lacking reddish gland dots, lines, or punctations. Stamens shorter than the corollas, the filaments 3–4 mm long, fused into a tube in the basal third, densely glandular. Staminodes absent. Styles 4–5 mm long. Fruits 3–4 mm long, broadly ovoid to nearly globose, the surface glabrous but with scattered gland-dots, sometimes in lines. Seeds 1.0–1.2 mm long, irregularly elliptic, oblong, or rhombic in outline, triangular in cross-section, dark brown. 2n=56, 84. June–August.

Introduced, uncommon, known thus far only from Camden and Shelby Counties (native of Europe, Asia; introduced sporadically in the northern half of the United States and adjacent Canada). Margins of ponds and bottomland prairies; also moist, open, disturbed areas.

Lysimachia vulgaris was first brought to the authors’ attention in 1994 by native plant enthusiast, Sue Vanderbilt (although an earlier specimen was later discovered during herbarium research). It was first reported for the state by T. E. Smith and Gremaud (2006), based on the Shelby County population. This species is no longer as commonly cultivated as an ornamental in the Midwest as it once apparently was. It is distinguished by its hairy stems, leaves dotted with orange or black glands, and flowers borne in terminal and axillary racemes and/or panicles.

Beckett (1995) studied this species in his garden in England and was surprised to find that the stoloniform, but well-branched rhizomes of L. vulgaris can spread horizontally at or just below the soil surface for distances as long as 2.5 m before tip-rooting and giving rise to a new plant.