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.