Lysimachia ovoidea is a sprawling shrub, bark reddish brown, striate with stems 40-250 cm long, branched, often with numerous short lateral branches, young ones rusty tomentose, soon glabrate. The leaves are well-spaced to closely spaced and somewhat imbricate, alternate, sometimes those of young or lateral branches ternate, thin, coriaceous (leathery), broadly elliptic-ovate (ovals shaped-egg shaped) to narrowly or broadly elliptic or elliptic-lanceolate (lance-shaped) at 22-90 mm long, 8-45 mm wide. The veins are usually conspicuous and slightly raised on the lower surface, sparsely pilose when young, soon glabrate, apex abruptly acuminate to attenuate, base broadly cuneate to attenuate. The flowers are solitary in the axils of sometimes reduced leaves, 5-8-merous, pedicels 12-37 mm long, elongating to 20-45 mm long in fruit, ± rusty pilose. The corolla is reddish purple to burgundy, the veins darker, campanulate (bell-shaped) at 10-20 mm long, and the lobes obovate to narrowly obovate. Capsules are broadly ovoid to subglobose, 8-9 mm long, and are regularly dehiscent. The seeds are numerous, nearly black, irregularly shaped, 1.6-2.2 mm long, margins slightly winged, seed coat crustaceous. It occurs in open mesic to wet forest sites between 610–1,500 meters.