Plants apparently annual (but this not known with certainty), partially mycotrophic (receiving nutrients and water from associations with soilborne fungi) herbs, glabrous, with chlorophyll, but lacking root hairs. Stems erect or sometimes lax and twining. Leaves reduced to subulate scales, alternate or mostly opposite. Inflorescences paniculate or reduced to racemes. Inflorescences terminal, open racemes or slender panicles. Flowers with parts in whorls of 4. Calyces deeply lobed, the lobes nearly separate, subulate. Corollas narrowly funnelform to more or less bell-shaped, deeply lobed, white, yellowish white, or purplish-tinged. Fruits relatively thin-walled, ellipsoid to ovoid. Three species, eastern U.S., Canada.

In Bartonia the ephemeral stems are sometimes purplish-tinged at the base. Although said to be annual by most botanists, little is known of the life history of this genus. By analyzing the profiles of radioactive isotopes of carbon and nitrogen in plants of B. virginica relative to their abundance in the surrounding environment, Cameron and Bolin (2010) made a case for the preferential uptake of nitrogen from associated soilborne fungi and thus provided evidence that plants of Bartonia are able to parasitize these fungi. This phenomenon of parasitism of mycorhizal fungi by vascular plants is known as mycoheterotrophy or mycotrophy.