Lysimachia thyrsiflora

Perennial, rhizomatous herb with robust stolons.

20–80 cm high.

The stem is erect, maroon, and typically simple.

The leaf arrangement is opposite, rarely whorled. The lamina is simple, entire, maculate with dark spots and slightly amplexicaul. The proximal leaves are scale-like. The distal leaves are narrowly lanceolate.

The flowers are arranged in dense racemes with long peduncles at the leaf axils. The calyx and corolla consist of six or seven leaves. The petals are 4–5 mm long, yellow, narrow and maculate with red-black spots at the apex. The flowers are bisexual. The gynoecium consists of a single style. The stamens exceed the corolla.

The fruit is a globose capsule (1.5–3 mm).