Description: This native perennial plant is about
½–1' tall and more or less erect. Smaller plants are unbranched,
while larger plants branch occasionally. There is a small tuft of basal leaves,
from which a central stem with alternate leaves develops. The stem is green and
glabrous. The leaves are up to 3" long and 1" across, becoming smaller as they
ascend the stems. They are obovate (spoon-shaped), hairless, and smooth along
the margins. The lower leaves taper to petiole-like bases, while the upper
leaves are sessile. Each upper stem terminates in 1 or 2 racemes of flowers.
The central stalk of this raceme zigzags between the pedicels of the flowers;
it is green, glabrous, and up to 5" long. The slender pedicels are about
½" long; they curve outward and upward. Each pedicel often has a single
scale-like bract near its middle. Each flower is about 1/8" across, consisting
of a short corolla with 5 white lobes, a globoid calyx with 5 small teeth along
its upper rim, 5 stamens with yellow anthers, and an inferior ovary with a
short style. The calyx is green, glabrous, and persistent. The flowers begin to
bloom from the bottom to the top of the raceme. The blooming period occurs
during the summer and early fall for about 2-3 months. Each flower is replaced
by a globoid seed capsule about 1/8" long with 5 small teeth along its upper
rim. This capsule contains many small seeds and eventually turns brown. The
root system consists of a tuft of shallow fibrous roots. This plant spreads by
reseeding itself.
Cultivation: The
preference is light shade to partial sun, wet conditions, and mucky or rocky
soil. This plant can grow in shallow water.
Range & Habitat: Brookweed occurs occasionally
in most areas of Illinois, except the NW portion of the state, where it is rare
or absent (see
Distribution
Map). Habitats include swamps, borders of small streams in wooded areas,
vernal pools, and soggy areas of floodplain woodlands. Brookweed occurs
primarily in shaded or partially shaded wetlands of wooded natural
areas.
Faunal Associations: There is
very little information about floral-faunal relations for this species.
Robertson (1928) observed a single Dance Fly, Empis clausa, visiting the
flowers for nectar. White-Tailed Deer have been observed eating the
foliage.
Photographic
Location: An alder swamp in Busey Woods at Urbana, Illinois, where
this species is uncommon. The leaves of the photographed plants are muddy from
being submersed in water.
Comments:
Brookweed can be difficult to find because it often occurs in obscure areas of
deciduous woodlands that are soggy and gloomy. The best time to look for this
species is during a drought when the wetlands where it occurs are more
accessible to foot-traffic. There is no other member of this genus in Illinois.
Brookweed doesn't closely resemble any other floral species in the state. It
vaguely resembles some of the Stellaria spp. (Chickweeds) or
Cerastium spp. (Mouse-Eared Chickweeds), but Brookweed has alternate
leaves, while the leaves of both Chickweeds and Mouse-Eared Chickweeds are
opposite. Distinctive characteristics of Brookweed include its globoid shiny
calyxes, the zigzag stalks of its racemes, and its hairless foliage. Other
scientific names for this species include Samolus valerandii parviflorus
and Samolus floribundus. Another common name is Water Pimpernel.