Rocky Mountain pond-lily (Nuphar lutea ssp. polysepala) belongs to the Nymphaeaceae (the Waterlily family). It is a perennial herb that is native to western North America. This herb grows in shallow ponds and slow streams, usually 60-300 cm deep at elevations below treeline. The leaves are leathery, round to ovate, 10-30 cm long. They are usually floating but are sometimes partially or wholly submersed. The flower is cup-shaped, floating or rising above water, about 10 cm across, yellow, often tinted green or red. The flowers bloom from June to August.