American cancer-root (Conopholis americana)
Orobanche americana L.
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name for American
cancer-root is Conopholis americana (L.) Wallr.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This native perennial plant is 4-8" tall and unbranched. It consists
of a rather thick spike of flowers, while the leaves are reduced to scales.
During the late spring this spike is cream-colored and hairless. Underneath
each flower, there is an ovate scale up to ½" long that quickly turns brown.
They are densely crowded all around the spike, and begin to bloom from
the bottom to the top.
Flowers: Each flower is about ½" long, consisting of a tubular corolla and
a tubular calyx. Both the corolla and calyx are cream-colored, although the
teeth of the calyx soon turn brown and wither away. The rest of the calyx
wraps around the base of the corolla. The corollas of young flowers are
initially semi-erect, but they spread outward from the spike with age. Each
corolla has a convex upper lip that functions as a hood, while the poorly
defined lower lip is smaller in size. Within the corolla, there are 4 stamens
near the interior of the upper lip, and a single stout style that develops
along the lower lip. Both the style and filaments of the stamens are white,
while the anthers are grey. When the flowers are blooming, some of the
stamens and styles may be exerted from their corolla tubes. There is no
noticeable floral scent.
Fruit/Seeds: Each flower is replaced by a seed capsule containing many
small seeds; this seed capsule is longer than it is wide. As the summer
progresses, the flowering spike begins to wither and becomes brown.
It can persist through the winter, by which time it has become shriveled
Roots: The root system is parasitic on the roots of Quercus spp. (Oaks);
the suckers of the parasitic roots cause the formation of large rounded
knobs on the roots of the host tree. Because cancer-root doesn't produce
chlorophyll, it is dependent on the host tree for its nourishment. Small
clusters of flowering spikes often develop from the same root system.
REGENERATION PROCESS: American cancer-root propogates itself
HABITAT TYPES: Habitats include upland woodlands, bluffs, wooded
slopes and ravines, and savannas. In all of these habitats, Quercus spp.
(Oaks) are invariably present. The flowering spikes of Americn cancer-root
often develop in areas where the leaf litter is scant. The greatest threat to
local populations is the invasion of Acer saccharum (sugar maple) in oak
woodlands as a result of fire suppression.
SITE CHARACTERISTICS: This parasitic plant is indifferent to light
levels. It requires the presence of an oak tree or its saplings at a well-
drained site where the soil is not too compacted.
SEASONAL DEVELOPMENT: The flowers bloom during the late
spring or early summer (May into June) for about 3 weeks.
GENERAL DISTRIBUTION: American cancer-root is found through-
out the eastern parts of the United States and Canada, ranging from
Florida north to Maine and into the Canadian maritime provinces (except
Newfoundland and New Brunswick). It naturally occurs west to the east-
ern Mississippi and Missouri River states (also Iowa) and into the Cana-
dian provinces west from Quebec to Manitoba.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: There is insufficient information pertaining
to the pollinators of American cancer-root. Bumblebees are known to pol-
linate one-flowered broomrape (Orobanche uniflora), a related species.
Black bears forage on the flowering spikes of American cancer-root after
they come out of hibernation and deer may browse on the flowering spikes
occasionally. Because it is possible that the seeds can survive passage
through the gastrointestinal tract, such animals may help to disperse the
seeds to new locations.
Despite the common name of this plant, there is no scientific evidence that
it has any cancer prevention or cancer causing properties. There is some
evidence of historical use by Native Americans of a related Mexican species
(Conopholis alpina), as an anti-tuberculosis treatment, but it is not know if
this was an effective treatment.
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