Geocaulon lividum (false toadflax) is a hemiparasitic perennial plant with orange berry-like fruits. Plants grow 10-30 cm tall, arising from a creeping rhizome. Leaves are alternate, elliptic to oval and membranaceous, turning purple with senescence. This species is frequently infected with a virus that causes the leaves to have a characteristic variegated appearance with pronounced yellow mottling frequently apparent. Stems are hairless and unbranched. Flowers grow along the stem in clusters of 2-3, with five green tepals. Only the middle flower of the cluster is perfect, with others containing stamens only. Geocaulon lividum parasitizes the roots of other plants. Fruit is a mealy orange to red drupe containing a single seed. The fruits are edible but unappetizing. Geocaulon lividum is easy to identify based on the presence of orange fruits growing in leaf axils on the stem of an upright herb.
Geocaulon lividum is a parasitic perennial plant that flowers early in the season; fruits develop slowly and are mature in the late fall. The foliage turns maroon-red in the fall.
Plants are monoecious with both bisexual and staminate flowers. Nothing is known about the pollination of Geocaulon lividum. The fruit is a one-seeded drupe, potentially eaten by small mammals and birds. G. lividum is known to spread vegetatively by its rhizomes. This species is hemi-parasitic: it photosynthesizes, but also has specialized structures that tap into the roots and rhizomes of trees and shrubs, stealing water and sugars.
Geocaulon lividum sometimes develops a distinctive patterning on it's leaves that is believed to be caused by a mosaic virus. G. lividum is also a secondary host for the fungus Comandra blister rust (Cronartium comandrae) which affects pine trees, particularly in western North America.
The berries are edible, but not necessarily desirable. The Dena'ina used leaves as poultice for cuts, and made a tea of the roots or chewed berries for stomach problems, sore throats and tuberculosis (Kari 1995).
Geocaulon lividum is endemic to North America, occurring from Alaska eastward to Newfoundland and southward to Washington state, Idaho and Montana, and also in the Great Lakes region to New England in the east. Geocaulon lividum occurs in eastern and southern Alaska north to the southern Brooks Range, but is rare in western Alaska and absent from the Alaska Peninsula. In Denali, this species is common and widespread in the boreal regions of the park on both sides of the Alaska Range.
Geocaulon lividum is a lowland species that is found from 154 m to 973 m, with an average plot elevation of 362 m. This species slightly prefers south facing aspects. It is more common on low to moderately sloped sites with an average plot slope of 6 degrees.
Geocaulon lividum is a lowland species that is parasitic on roots of various boreal forest plants such as spruce (Picea spp.), birch (Betula spp), willow (Salix spp.), alder (Alnus spp.) and twinflower (Linnea borealis). It is generally found in acidic, nitrogen-poor soils.