Stems erect, usually simple or sparingly branched, 3-6.5 dm, stipitate-glandular, especially distally; rhizomes somewhat thickened and almost fleshy; bulblets absent. Leaves whorled; petiole absent; blade lanceolate, 2-5.5 × 0.8-2 cm, base rounded to truncate, not decurrent, margins entire, slightly revolute, eciliate, apex acute, surfaces dark-punctate, especially abaxially and/or apically (sometimes obscurely so), glabrous; venation palmate, main veins 3-5. Inflorescences mostly terminal, somewhat leafy racemes, 3-10 cm. Pedicels 0.4-2 cm, stipitate-glandular. Flowers: sepals 5, calyx streaked with dark resin canals, 3-6 mm, minutely stipitate-glandular, especially distally, lobes narrowly lanceolate, margins thin; petals 5, corolla yellow, streaked with reddish black resin canals, rotate, 6-9 mm, lobes with margins entire, apex acute to acuminate, stipitate-glandular; filaments connate 1-1.5 mm, shorter than corolla; staminodes absent. Capsules 3-4 mm, not punctate, glabrous. 2n = 42.

Flowering early summer. Swamp margins, wet pine savannas and pocosins; 0-300 m; N.C., S.C.

The common name 'rough-leaf yellow loosestrife' includes a misinterpretation of the specific epithet, which originally referred to the whorled leaves resembling those of some species of Asperula Linnaeus (Rubiaceae).

Lysimachia asperulifolia is in the Center for Plant Conservation´s National Collection of Endangered Plants.