Fl. primrose yellow; perianth segments very broadly ovate in outline, rounded or squarish at apex, with whitish mucro prominent, a little reflexed, smooth, overlapping 1/3 to 1/2; inner segments more narrowly ovate, very slightly mucronate, nearly spreading, with margins wavy; corona cup-shaped, lightly ribbed, darker in tone than the perianth, with mouth straight or slightly incurved, wavy, rim entire or obscurely crenate.