Spatterdock (Nuphar advena)
Spatterdock, or yellow pond-lily (Nuphar advena), is an emergent perennial aquatic plant widespread in the eastern United States, but also occurring in southern Canada (Ontario). It commonly inhabits shallow freshwater ponds, where its rhizome is anchored in a muddy bottom and, under favorable conditions, can produce numerous vegetative colonies. Its large (up to 16 inches long) cordate-ovate dark-green leaves are mostly held slightly above the water surface or are found floating, and it requires at least partial sunlight to flower. The yellow flowers are solitary, close for the night, and usually also emerge several inches from the water. They consist of two perianth whorls, the outer fleshy green sepaloid tepals, and the inner yellow petaloid tepals, surrounding numerous staminoids with nectaries, stamens with anthers, and carpels. Flower morphology helps to distinguish spatterdock from the closely related genus Nympheae. Spatterdock can reproduce both by seed and by rhizome. As a part of its ecological system, spatterdock provides habitat for numerous invertebrates, and its rhizomes are eaten by some semi-aquatic animals such as muskrats.
Phylogenetically, plants from the genus Nuphar are basal angiosperms, as it is a member of the Nymphaeales order which is sister to almost all extant angiosperms. As such, Nuphar advena has received much attention and serves as a model species in evolutionary studies shedding light on key events in angiosperm development and diversification, for example in the Ancestral Angiosperm Genome Project. In-depth studied features include potential ancient genome duplication, chloroplast genome, and floral morphology. Our current investigation of the origins of rhizomatousness is of similarly great evolutionary relevance.