Polygonum dentoceras (synonym Polygonella myriophylla)[1] is a rare species of flowering plant in the knotweed family known by the common names sandlace, woody wireweed, and Small's jointweed.

[3] It engages in allelopathy, the release of chemicals including gallic acid and hydroquinone, to prevent other plants from growing directly next to it.

[6][8] Visitors to the flowers include the bee Dialectus placidensis, the shore fly Allotrichoma abdominalis, and the hairstreak butterfly Hemiargus ceraunus.

[3] Threats to this species include the destruction of its habitat during the conversion to residential and agricultural property, particularly citrus groves.

[9] Fire suppression may have a negative effect on this plant, because it is adapted to a habitat that depends on wildfire.