This herbaceous parasitic vine is a summer annual that is several feet
along. It clings to adjacent vegetation using suckers (haustoria) on
its stems. Lacking chlorophyll and a significant root system, this vine
is dependent on its host plants for water and nutrients. The stems are
usually pale yellow, sometimes becoming pale orange with age; they are
glabrous and terete. Alternate leaves along the stems are reduced to
tiny scales, or they are absent altogether. Small clusters of nearly
sessile flowers occur at intervals along the stems. The peduncles and
pedicels of these flowers are pale yellow to pale orange and glabrous.
Each flower spans about 3 mm. (1/8" across), consisting of a white
corolla with 4 lobes, a light green calyx with 4 lobes, 4
stamens, and an ovary with a pair of divergent styles. Less often, a
flower may have a corolla with 5 lobes, a calyx with 5 lobes, and 5
stamens. The lobes of the corolla are deltate-ovate in shape and
ascending to widely spreading. The calyx is glabrous with rounded
lobes; it is shorter than the corolla. Both the corolla and calyx are
short-tubular and bell-shaped (campanulate). At the base of the stamens
within the corolla, are fringed scales that require at least a 10x
hand lens to see. There are no floral bracts
underneath the flowers. The blooming period occurs from mid-summer to
early fall, lasting about 1½ months. There may be a mild floral
fragrance. In the absence of insect pollinators, the flowers are
self-fertile; they are replaced by globoid seed capsules spanning 3-5
mm. across. The glabrous seed capsules are surrounded by the withered
remains of their corollas; they are initially light green, but turn
brown at maturity. Each capsule is 2-celled, and each cell contains 2
seeds. The capsules eventually split open to release their seeds. The
seeds are about 1.5 mm. long (or slightly more), ovoid in shape, and
slightly compressed. There is a rudimentary root system at the seedling
stage, but this is abandoned shortly after a suitable host plant has
been found. If no host plant is found, the seedling dies within a few
This vine is typically found in wet to moist
areas that are exposed to sun or partial sun. It cannot survive without
a suitable host plant, although apparently many species of
moisture-loving plants and shrubs can serve this purpose. Examples of
suitable host plants include buttonbush (Cephalanthus occidentalis
water willow (Justicia
), false nettle (Boehmeria cylindrica
asters (Aster spp.
goldenrods (Solidago spp.
), and even horsetails (Equisetum spp.
Soil type depends on the
preferences of host plants, but can consist of sand, silt, loam, or
muck. This vine can significantly weaken any host plant that it comes
in contact with.
The native Buttonbush
Dodder is scattered throughout Illinois, where it is uncommon to
occasional (see Distribution
). Habitats include floodplain
woodlands, swamps, soggy
thickets along rivers, marshes, and wet prairies. This vine occurs
in both sandy and non-sandy wetlands.
Robertson (1929) observed a small Halictid bee, Lasioglossum coriaceus
sucking nectar from the flowers of Buttonbush Dodder. Other small bees
also visit the flowers for nectar, and possibly some moths (Müller,
1873/1883). According to Georgia (1913), the seeds of dodders can pass
through the digestive tracts of grazing animals (e.g., cattle &
horses) and remain viable. Thus, these animals may help to distribute
these vines into new areas.
A sandy marsh at the Heron Boardwalk in
Buttonbush Dodder has a fairly typical appearance for the parasitic
vines of this genus, although it is somewhat unusual in having 4-parted
flowers (4-lobed corollas, 4-lobed calyces, and 4 stamens), rather
than 5-parted flowers (5-lobed corollas, 5-lobed calyces, 5 stamens).
Unlike other dodder species (Cuscuta
the corolla lobes of Buttonbush Dodder usually spread outward rather
than remain erect. Thus, it is a fairly easy species to identify during
the blooming period. Some taxonomists have placed dodder species in the
Morning Glory family (Convolvulaceae).