spatterdock, yellow waterlily, cow lily
temperate Northern Hemisphere
Nuphar japonica DC.
N. lutea (L.) Sm.
N. pumila (Timm) DC.
Nuphar advena (Aiton) W.T. Aiton, N. pumila, and N. lutea have been introduced into various European countries within Nuphar's overall native distribution. N. lutea is also introduced into New Zealand.
a significant weed in some countries
Perennial. Stem a slender or stout rhizome, usually bearing old leaf scars. Leaves in a basal rosette arising from buried rhizome, submersed, floating, or emergent; petiole smooth, greatly elongate; leaf blade ovate, deeply sagittate to orbicular with deep sinus, venation palmate; margin entire. Inflorescence a large, solitary flower borne above water surface on a long pedicel. Sepals 6, imbricate, outer green, inner green or yellow; petals numerous, yellow, smaller than sepals, linear to oblong, scale-like to stamen-like, bearing nectary on abaxial surface; stamens numerous. Dispersal by seed or sometimes by daughter plants off rhizome.
lakes, ponds, and streams
The taxonomy of Nuphar is poorly known; numerous subspecies are described, but the genus is poorly delimited. Its rhizome is edible and young leaves are used as tea.