A medium-sized dandelion with prostrate to ascending, dark green, rather hairy, lanceolate leaves with crisped  dentate interlobes heavily blotched blackish. Petioles winged, the outer whitish, the inner pink; mid-ribs pinkish, hairy. Leaf side-lobes 4-5, triangular, recurved, blackish-dentate on the distal margin. Homophyllous; leaf end-lobes triangular-sagittate, acute to obtuse. Exterior bracts recurved, rather narrow (<3.5 mm wide), purple on the upper surface. Capitulum about 45 mm diameter, flat when expanded.  Structurally, T. nigridentatum resembles T. pannulatiforme in many ways and may be closely related, but the extent to which this very dentate dandelion is pigmented is distinctive.