Fl. rounded; perianth segments very broadly ovate, rounded at apex and a little truncate, slightly mucronate, pure white, spreading or a little reflexed, concave at apex, smooth, overlapping half; the inner segments a little narrower, more deeply truncate, more nearly spreading and plane; corona bowl-shaped, closely ribbed, opening pure white, becoming yellowish white, with greenish gray in tube, mouth expanded and lightly frilled.