Fl. forming a double triangle; perianth segments broadly ovate, blunt, yellow, with white mucro more or less prominent, spreading or a little reflexed, plane or somewhat concave, smooth and of heavy substance, overlapping half; the inner segments more narrowly ovate, more nearly spreading at base, slightly reflexed towards apex, with margins wavy; corona cylindrical, smooth, mouth widely expanded, even, with rim very deeply notched and regularly crenate.