This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
An erect perennial leafy herb, with slender rootstocks, opposite sessile lanceolate entire leaves, the lower much smaller or reduced to scales, and small yellow flowers in axillary peduncled spike-like racemes or heads. Calyx 5-7-divided, the sepals linear, slightly imbricated. Corolla deeply 5-7-parted, the tube exceedingly short, the segments narrow. Stamens 5-7, exserted; filaments slender, glabrous, slightly united at the base, alternating with as many small tooth-like staminodia at each sinus of the corolla. Ovary globose-ovoid; ovules few or several; style slender, equalling or exceeding the stamens; stigma capitate. Capsule 5-7-valved, few-seeded. Seeds not margined, somewhat angled. [In honor of Naumburg.]
A monotypic genus of the north temperate zone.
Lysimachia thyrsiflora L. Sp. Pl. 147. 1753. Naumburgia guttata Moench, Meth. Suppl. 23. 1802. Naumburgia thyrsiflora Duby, in DC. Prodr. 8: 60. 1844.
Glabrous or somewhat pubescent; stems simple, erect, often tufted, 1°-2 1/2° high. Leaves 2'-4' long, 4"-10" wide, the upper lanceolate or oblong-lanceolate, acute or acuminate at the apex, narrowed at the base, the lower smaller, the lowest reduced to ovate scales or these deciduous; peduncles solitary in the axils, rather stout, 1/2'-1/2' long; racemes dense, oblong or ovoid, 1/2'-1' long, spike-like; pedicels very short; flowers 2" - 3" broad; sepals usually spotted; corolla-segments yellow with black spots; style very slender; anthers oblong; capsule globose, black-spotted, when mature slightly longer than the sepals, shorter than the style.