Plants to 100 cm (weakly rhizomatous). Stems 5-ribbed. Basal leaves: blades (usually with 5 main veins from bases) ovate to elliptic, to 18 cm, margins entire. Cauline leaves: proximal petiolate, ovate, margins crenulate; distal petiolate or sessile, smaller. Involucres 12-15 mm. Phyllaries (light green) ovate, midvein wings uniform or highest at apices. Corollas white or light green, (9-)11-12 mm. Cypselae fusiform, 5 mm (green); pappi 7-8.5 mm. 2n = 50, 52. Flowering May-Jul. Dry sand ridges, pine-oak woodlands; of conservation concern; 0-20+ m; Fla. Arnoglossum floridanum is known only from central peninsular Florida.