Geocaulon

Geocaulon is a genus of flowering plants in the family Santalaceae, commonly known as the sandalwood family. These plants are hemiparasitic shrubs, meaning they obtain some of their nutrients from host plants while also photosynthesizing.

Geocaulon species are native to North America. They are characterized by their underground stems (rhizomes) and small, inconspicuous flowers. The most well-known and only currently recognized species within this genus is Geocaulon lividum.

Geocaulon lividum, commonly called northern comandra or false toadflax, is a perennial plant found in a variety of habitats, including grasslands, open woodlands, and rocky slopes. It parasitizes the roots of various host plants, including grasses, shrubs, and trees. This hemiparasitic relationship allows Geocaulon lividum to supplement its nutrient intake, particularly water and minerals, from its host.

The plant's leaves are typically bluish-green and lance-shaped. The small, greenish-white flowers are arranged in clusters. Geocaulon lividum produces small, fleshy fruits that are dispersed by animals. It plays a role in the ecosystems where it is found, influencing plant community structure through its parasitic interactions.