Spatterdock
Nuphar advena
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 flowers of Spatterdock (Nuphar advena) are pollinated by an oligolectic bee, Lasioglossum nelumbonis, which collects pollen, and such semi-aquatic leaf beetles as Donacia piscatrix (False Longhorn Leaf Beetle) and Galerucella nymphaeae (Waterlily Leaf Beetle), which feed on pollen. A Syrphid fly, Parhelophilus divisus, was also observed to visit the flowers for pollen, but it is unlikely to be an effective pollinator (Robertson, 1929; Lovell, 1915). Various insects feed on the leaves, rootstocks, petioles, and/or floral stalks of this plant, including the larvae and adults of semi-aquatic leaf beetles (Donacia spp.), larvae of Crambid and Noctuid moths (Parapoynx spp., Bellura gorytoides, etc.),  larvae of some caddisflies (Triaenodes spp., etc.), and the Pond Lily Planthopper (Megamelus davisi); the Insect Table has a more complete listing of these species. Some vertebrate animals also use Spatterdock as a source of food. For example, its seeds are eaten by such waterfowl as the Wood Duck, Black Duck, Lesser Scaup, Ring-necked Duck, Common Goldeneye, and Trumpeter Swan (Martin et al., 1951/1961; Bellrose, 1942/ 1976). The rhizomes are sometimes eaten by the American Beaver and Muskrat, while the American Moose feeds on the foliage. Some turtles also feed on either the seeds or foliage, including the Snapping Turtle, Painted Turtle, and Stinkpot (Sternotherus odoratus); see Martin et al., 1951/1961; Hamerstrom & Blake, 1939; and Ernst et al., 1994.

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.

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