Bulb rhizomatous, narrowly ovoid, 2-4 × 1-3 cm; basal plate 1-2 cm; neck 3-10 cm; tunic light gray. Leaves deciduous, 4-7, arching low, often appearing prostrate, 2.4-5.2 dm × 1-2.5 cm, not highly coriaceous; blade narrowly liguliform or narrowly oblanceolate, apex acute. Scape 2.4-4 dm, 2-edged, glaucous; scape bracts 2, enclosing buds, 3-5.5 cm × 5-12 mm; subtending floral bracts 2.7-3 cm × 3-4 mm. Flowers 2-3, rarely more, opening sequentially, intensely fragrant; perianth tube green, 5-9(-10.5) cm; tepals slightly ascending, tinged green on keel, 7-10 cm × 4-6 mm; corona white with small green eye, becoming rotate at full anthesis, shortly tubulose proximally, (2.5-)3-4 × 4-5 cm, margins between free portions of filaments irregularly and coarsely dentate; free portions of filaments inserted on flat sinal base, suberect, white, 2.5-3 cm; anthers 1-1.7 cm, pollen golden; ovary green, ovoid, ca. 1 cm × 5 mm, ovules 2-4 per locule; style green in distal 1/3, fading into white proximally, 13-17 cm. Capsules subglobose, ca. 2.5 × 2.5 cm. Seeds elongate, 1.3-2.1 × 0.7-1.2 cm. 2n = 42. Flowering early--mid spring. Floodplain forests and sandy stream and river banks; 0 m; Fla., Ga. Hymenocallis duvalensis is another southeastern spider-lily that is not well known (S. Puffenbarger and G. L. Smith 1993; G. L. Smith et al. 1999). It forms dense colonies along the interior floodplains of streams in north Florida, extending to the Ochlockonee River and up into south-central Georgia. Its arching, deep green, liguliform or sometimes narrowly oblanceolate leaves and rotate staminal corona at full anthesis make it easily identifiable in the field. Newly opened flowers are intensely fragrant. This species would make a handsome addition to the gardens of the South. Herbarium specimens of Hymenocallis duvalensis may be hard to distinguish from those of H. crassifolia. The less coriaceous, arching leaves and rotate staminal corona are excellent field characteristics, but they are not readily discernible on herbarium specimens. Characteristics that are more reliable for identification on some herbarium specimens are the narrowly oblanceolate leaves, the width of the corona (unbroken), and the width of the perianth tube. The tube is often more robust than in H. crassifolia, measuring 1.5-3.5 mm wide. Numerous herbarium sheets have been misidentified as either H. crassifolia or H. rotata.