Musk thistle or nodding thistle, is a member of the Asteraceae or sunflower family. Musk thistle can grow up to 6 feet tall. Upright stems of the plant are winged and can be single or multiple and highly branched. Rosette leaves of the plant are elliptic to lanceolate and pinnately lobed with each lobe ending in a spine. Leaf surfaces are green, glabrous to densely pubescent with margins ranging from white to purple in color. Cauline leaves, of or attached to the stem, are similar to the rosette leaves, but are smaller, simple, alternate, and decurrent. Flower heads are terminal, solitary, 1 1/2 to 3 inches in diameter, and usually bent over. Flowers are typically deep rose, violet, or purple, or occasionally white in color and have very characteristic brown bracts that resemble a pine cone. Musk thistle seeds are shiny, yellowish-brown in color, 3/16 inches long with a plume of white hair-like fibers. There are two sub-species of the plant that differ in flower size and pubescence in North Dakota.

Musk thistle is considered a noxious weed under North Dakota state law, thus landowners are required to eradicate or control the spread of the plant.