Rayless goldenrod (Isocoma pluriflora
) is an erect, bushy, unbranched perennial shrub that's native to the Southwestern United States and Northern Mexico. It has narrow leaves and clusters of yellow flower heads at the top of the stems, each head with 8 to 21 yellow disc flowers.
is toxic to all livestock, causing a condition known as trembles. Daily consumption of only 1-1.5% of an animal's body weight for a week or more can poison the animal which could potential lead to its death. Poisoning is sporadic due to the considerable variation in the quantity of its toxins, which research suggests are benzofuran ketones (tremetone, dehydrotremetone, 6-hydroxytremetone, and 3-oxyangeloyl-tremeton).