Stems slender, weak, flattened. Leaves: basal blades 40-100 × 10-25 mm, dentate, apices obtuse. Phyllaries broadly lanceolate, thin, scarcely keeled, 4-5 mm, stellately spreading in fruit. Corollas 6-10 mm. Cypselae straight, 4-5 mm. 2n = 16. Flowering May-Jun. Cultivated fields, disturbed areas, low boggy areas; 10-100 m; introduced. Oreg.; Asia (China, Japan, Korea). Lapsanastrum apogonoides is distinguished by its prostrate habit, weak stems, lyrate leaves, and 5 phyllaries spreading in fruit.