Plants 9-75 cm; taproots seldom branched. Stems 1-7+, erect to ascending, ± purplish, glabrate, sometimes ± sparsely villous distally. Leaves 10+, erect to patent; petioles ± narrowly winged; blades broadly oblance-olate to narrowly obovate (often runcinate), 15-47.5 × 2.5-9 cm, bases attenuate, margins usually shallowly lobed to sometimes lacerate (mostly proximally), lobes retrorse or straight, broadly deltate to triangular, sometimes antrorsely curved apically, acute to acuminate, teeth 5-7 on lobes and in sinuses, irregular, triangular or sometimes lanceolate, terminals broader than laterals, apices obtuse to bluntly short-caudate or -acuminate (rarely acute), faces glabrous or glabrate to sparsely pilose or villous. Calyculi of ca. 18 , reflexed to recurved, ovate to broadly lanceolate bractlets in 3 series, 8-11 × 2-5 mm, margins narrowly scarious, sometimes proximally more widely so, apices acuminate, hornless, ± scarious-erose, tips often purplish and blackish. Involucres dark green, often purplish-tinged, campanulate, (13-)15-23 mm. Phyllaries 14-18 in 2 series, lanceolate to linear (outer) or ovate to lance-ovate (inner), 1.2-4 mm wide, scarious, narrowly (outer, distal part of inner) or widely (proximal part of inner), apices long-acuminate, hornless, scarious, erose, hyaline, purplish-grayish. Florets ca. 150; corollas yellow (outer dark gray striped abaxially, also purplish), 13-17 × 1-1.3 mm. Cypselae olive-tan to tan, bodies oblanceoloid, 2.8-3.8 mm, cones terete, 0.9-1 mm, beaks slender, 8-12 mm, ribs 5, wide (with 2-3 rows of tubercles or spines), faces proximally tuberculate, muricate in distal 1/3-1/2, distalmost spines sometimes very sharp, fused in pairs and flattened; pappi white to creamy, 6.5-7 mm. Flowering summer. Seaside calcareous slopes and grassy taluses or clifftops; 0-30 m; Nfld. and Labr. (Nfld.), Que.; Maine. Taraxacum latilobum is known only from the Gulf of St. Lawrence and adjacent areas.