Leaf blade dull green, to 5 mm wide. Spathe 2–2.8 cm. Flowers erect to slightly inclined; perianth white, sometimes flushed pink abaxially, more so with age, funnelform, 3.6–4.6 cm; perianth tube green, 0.2–0.4 cm, increasing in diam., 1/10 or less of perianth length, ca. 1/4 filament length, ca. 1/6 spathe length; tepals not reflexed, distal 3 more erect than proximal 3; stamens diverging, in 2 distinctly subequal sets with anthers overlapping ca. 50 percent; filaments filiform, 1–1.3 cm; anthers 4–7 mm; style 2.2–2.5 cm, longer than perianth tube; stigma 3-fid, exserted ca. 10 mm beyond anthers; pedicel 2.3–3.3 cm, usually exceeding spathe. 2n = 28.

Flowering summer (Jun--Aug). Sandy loam; 0--50 m; introduced; Fla.; Mexico; West Indies (Cuba).

Zephyranthes insularum was based on plants from a garden in Key West, Florida, and from Santiago de las Vegas, Cuba. Its native locale is uncertain. It persists and is locally adventive in Florida.