spatterdock

[ spat-er-dok ]
/ ˈspæt ərˌdɒk /

noun

any of various water lilies of the genus Nuphar, having globular yellow flowers and growing in lakes or sluggish streams, especially N. advena, of the eastern U.S.
Also called cow lily.

Origin of spatterdock

An Americanism dating back to 1805–15; spatter + dock4