Conopholis americana (koh-noh-FOH-lis a-mer-ih-KAY-nah)
Family: OrobanchaceaeNativeHerbaceous
HerbaceousNative
Cancer Root is an herbaceous, perennial, parasitic plant in the boomrape (Orobanchaceae) family. It typically grows from 3 to 8 inches in height, an inch wide, and is unbranched. Inflorescences that look like the cones from a conifer break through the surface of the soil when the plants are approximately four years old after they have been growing underground attached to oak roots. As it matures, the plant produces a rather thick spike of flowers, while the leaves are reduced to scales. The spike is cream-colored and hairless in late spring and the flowers bloom from the bottom to the top of the spike for a short time in spring and summer. As the summer progresses, the flowering spike withers and becomes brown and resembles a pine cone as it becomes dry with age. The genus name Conopholis comes from Latin for 'cone' and 'scale' and refers to the appearance of the stems with scale-like flowers that resemble upright golden cones. Despite the common name, there is no evidence that the plant has anything to do with cancer. Cancer Root grows in large areas of Eastern America on organically rich forest soils. It needs well-drained soils but grows in a wide variety of light conditions. This plant does not photosynthesize, hence its lack of the green pigment chlorophyll. The root system is parasitic on the roots of Quercus spp. (Oak Trees); 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. This plant spreads to new locations by reseeding itself. Black Bears coming out of hibernation forage on the flowering spikes and there is some evidence that deer browse on the spikes occasionally. It is possible that such animals may help to disperse the seeds to new locations. Diseases, Insect Pests, and Other Plant Problems: No known diseases or insect pests.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Dappled Sunlight (Shade through upper canopy all day) | Deep shade (Less than 2 hours to no direct sunlight) | Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter
Soil drainage
Good Drainage | Moist | Occasionally Dry
Available space
Less than 12 inches
NC region
Coastal; Mountains; Piedmont
Growth rate
Slow
Maintenance
Low
Canopy layer
4 - Herbaceous
Form & Appearance
Habit / form
Erect
Leaf color
Brown/Copper; Gold/Yellow
Leaf shape
Lanceolate; Ovate
Leaf size
< 1 inch long
Hairs present
No
Leaf detail
No true leaves, brown ovate 1/2 inch long scales appear underneath each flower. Flowers emerge among the lanceolate or ovate, pointed, yellow-tan scales on upper part of a fleshy stalk.
Flower color
Cream/Tan; Gold/Yellow
Flower value
Showy
Flower form
Spike
Flower shape
Tubular
Flower size
< 1 inch
Flower detail
Cream to golden yellow spike inflorescences densely packed around erect stems resembles cones or cobs of corn. These appear as early as April in warm areas or as late as July and bloom for a period of about three weeks. Tubular flowers are 1/2" long, 5 parted, are downward facing and have a swollen base. Flowers bloom from the bottom of the spike to the top.
Bloom time
Spring; Summer
Fruit type
Capsule
Fruit detail
Each flower is replaced by a seed capsule containing many small seeds; this seed capsule is longer than it is wide.
Stem detail
Thick (1/2 inch - 1 inch) stout unbranched stems.
Wildlife & Ecology
Native status
Native
Origin
E. Canada, Central & E. U.S.A., S. Mexico, Costa Rica to Panama