Lysimachia nummularia L.
Family - Primulaceae
Stems - Repent, tp +40cm long (and sometimes much longer), herbaceous, multiple from the base, typically simple, with 4 wings from deccurent leaf tissue. Wings to .7mm broad, forming vertical grooves along the sides of the stems.
Leaves - Opposite, petiolate. Petioles to +/-5mm long, glabrous, with a wide and shallow adaxial groove. Blades orbicular, to +/-2.5cm in diameter, glabrous, entire, somewhat cordate at the base, dark green above, lighter green below. Veins of the leaves impressed above, expressed below.
Inflorescence - Single axillary flowers. Peduncles to +/-2cm long, erect, glabrous.
Flowers - Petals typically 5 (sometimes 6), united at the very base and forming a small corolla tube. Tube to 1mm long. Free portion of petals glabrous, yellow, to +1.4cm long, 5-7mm broad, rounded at the apex, oblong-elliptic. Stamens 5(6), adnate at the base of the petals, erect, united at the base. Filaments yellow, broadest at the base and tapering to the apex, glandular puberulent, to 5mm long. Anthers yellow, to 2mm long. Ovary superior, green, glabrous, globose, 1.2mm in diameter. Style green, glabrous, 5mm long. Stigma small, purplish. Sepals 5(6), green, spreading, with the margins slightly revolute in the basal 1/2, ovate-lanceolate, acute to acuminate at the apex, to +/-7mm long, +/-5mm broad, glabrous.
Flowering - May - August.
Habitat - Streambanks, bottoms, ditches, roadsides. Also cultivated.
Origin - Native to Europe.
Other info. - This weedy yet attractive species can be found scattered throughout most of Missouri. The plant is an escape from lawns and gardens and is now well established in this state. Plants seldom flower, which is why I do not show flowers in the whole plant pic above, but rather spread by creeping stems which root at the nodes and create large mats if left unchecked. Steyermark mentions that the plant makes a good ground cover for shaded, moist areas.
Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 6-9-03.