Fl. forming a double triangle, 102 mm wide; perianth segments 41 mm long, very broadly ovate, blunt, prominently mucronate, vivid yellow, spreading, plane to a little concave, with midrib showing, of heavy substance, overlapping one-third to a half; the inner segments narrower, more nearly plane; corona 34 mm long, funnel-shaped, smooth, a darker tone than the perianth, mouth straight, wavy, with rim crenate.

Named for Nial Watson’s mother-in-law.