Water Lily family (Nymphaeaceae)
Description: This perennial wildflower is an emergent aquatic plant. The leaf blades are 6-12" long and about two-thirds as much across; they are usually held several inches above the water, although sometimes they float on the water's surface. The leaf blades are cordate-ovate in shape with smooth margins and blunt tips; each leaf is sharply cleft and divided into two basal lobes where its terete petiole joins the blade. Along the upper surface of each blade, faint pinnate venation can be seen; these veins dichotomously branch toward their tips. Both the blades and petioles are glabrous and more or less medium green; rarely are they pubescent.
Individual flowers are produced from stout pedicels that emerge a few inches from the water. Like the petioles of the leaves, the pedicels of the flowers are stout, glabrous, and terete. The globoid flower buds are covered with 3 outer sepals that are initially green. These buds open up slightly to reveal greenish yellow flowers spanning 1-3" across. In addition to the outer sepals, each flower has 3 inner sepals that are yellow, many small yellow petals, several rings of stamens, and a yellow compound pistil. The overlapping sepals are oval to nearly orbicular, forming a small cup-like structure around the compound pistil. The flattened apex of this pistil has 8-24 spreading stigmatic rays. The petals are largely hidden by the much larger sepals. The blooming period occurs from late spring to early fall, lasting about 3 months or more. Individual flowers are short-lived. Each flower is replaced by an ovoid fruit that is slightly constricted toward the apex; this fruit is about 1½" long and one-half as much across. Each fruit is divided into several cells, splitting open irregularly to release the rather large seeds (about ¼" long). The root system is very rhizomatous, producing vegetative colonies in shallow water.
Cultivation: Spatterdock requires a shallow wetland with about 1-5' of water and a muddy bottom. This should be a protected area that is free of strong water current, strong wind, and strong wave action. While clear water is preferred, Spatterdock also tolerates slightly muddy water. At least partial sunlight is required to produce flowers. It can spread aggressively in some locations.
Range & Habitat: The native Spatterdock occurs occasionally throughout Illinois; it is more common in southern and NE Illinois than elsewhere. In NE Illinois, Spatterdock may hybridize with the closely related Nuphar variegatum (Bullhead Lily). Habitats include swamps, ponds, protected coves along lakes, and shallow areas along slow-moving rivers. These wetlands are variable in their level of disturbance.
Faunal Associations: The primary pollinators of the flowers may be adult leaf beetles (Donacia spp., Galerucella spp.), whose larvae feed on the foliage. However, Charles Robertson (1929) reported only the Halictid bee Lasioglossum nelumbonis and the Syrphid fly Parhelophilus divisus visiting the flowers of Spatterdock; the former insect is a pollinator specialist of plants in the Water Lily and Water Lotus families. These insects fed on the pollen. The larvae of Galerucella nymphaeae (Waterlily Leaf Beetle) and several Donacia spp. feed on the foliage of Spatterdock (see Beetle Table). The caterpillars of the moths Bellura gortynoides (White-Tailed Diver), Homophoberia cristata (Water Lily Borer), Parapoynx obscuralis (Pyralid Casemaker Moth sp.), and Parapoynx maculalis (Pyralid Casemaker Moth sp.) also feed on the foliage. Apparently, some wetland birds eat the seeds of Spatterdock to a limited extent; this includes the Wood Duck, Ring-Necked Duck, and Virginia Rail. Muskrats and beavers will feed on the entire plant, especially the rhizomes and lower petioles. There are records of various turtles that use Spatterdock as a food source; these include Chelydra serpentina (Snapping Turtle), Chrysemys picta (Painted Turtle), and Stenotherus odoratus (Musk Turtle or Stinkpot).
Photographic Location: Protected cove of a small lake at Weldon Springs State Park near Clinton, Illinois.
Comments: Sometimes Spatterdock is referred to as Nuphar luteum macrophyllum; it is also called the 'Yellow Pond Lily.' This species is very similar to Nuphar variegatum (Bullhead Lily); the latter is restricted to NE Illinois. Sometimes these two species are regarded as different subspecies of Nuphar luteum. The Bullhead Lily is supposed to differ from Spatterdock as follows: 1) Its petioles become flattened toward the leaf blades, 2) the inner sepals are sometimes tinted red, and 3) the leaf blades usually float on the water surface, rather than being held above the water surface. The flowers of Spatterdock are exceedingly modest; they seem to be perpetually reluctant to open. The foliage of this species is reasonably attractive, but it has a tendency to deteriorate as the season progresses.