Source: Idaho's Noxious Weeds by Robert H. Callihan & Timothy W. Miller
BACKGROUND
Skeletonleaf bursage (Ambrosia tomentosa) is native to the Great Plains region. It spreads both by seed and creeping roots, keeping primarily on, but not limited to, dry or poorly drained sites.
DESCRIPTION
Skeletonleaf bursage is a perennialPlant that lives for more than 2 growing seasons up to 3 feet tall. Leaves are alternate, up to 5 inches long, and very deeply lobedA cut into a leaf from the edge toward the center; greater than toothed, but not quite compound with coarsely toothed marginsmargin: edge of the leaf. The lobesA cut into a leaf from the edge toward the center; greater than toothed, but not quite compound are reduced in size from leaf base to tip. The upper leaf surface is greenish-gray and may have rough hairs; the lower surface is white with short, dense hairs. Flower headsA group of flowers borne tightly together are ΒΌ inch wide and are produced from June through August. Each head contains inconspicuous yellow flowers that are either male or female (not both). Fruits are 2-seeded, light brown burs with up to 10 short spines. The plant has extensive horizontal roots.
DISTRIBUTION
Skeletonleaf bursage occurs from the desert Southwest to Wisconsin and Illinois and in these selected Idaho counties.
CONTROL
No biological control agents are available for Skeletonleaf bursage, but herbicides are available for control of this weed.