Plants 80-100+ cm. Stems strongly ridged. Basal leaves: (petioles 12-18+ cm) blades (lateral veins appressed to midveins 2-4 cm, then spreading) broadly ovate to narrowly oblong-lanceolate, 15-37 cm, margins usually entire, rarely sinuate or serrulate-denticulate. Cauline leaves: proximal petiolate, blades ovate (12-18+ cm, bases cuneate), margins serrate (apices acuminate); distal sessile, smaller. Involucres 10-12.5+ mm. Phyllaries (chalky white) ± ovate, midvein wings highest at bases. Corollas white, rarely tinged with pink, 9-10.5 mm. Cypselae cylindric to narrowly clavate, 4.2-5 mm; pappi 6-7 mm. 2n = 50. Flowering May-mid July. Poorly drained, acidic loamy sands, savannas, open pinewoods; of conservation concern; 0-10 m; Fla. Arnoglossum album is known only from Bay and Gulf counties.