Common Name
Jimmy weed, burrow weed, rayless goldenrod
Botanic Name
Isocoma pluriflora (Haplopappus heterophyllus, Iscoma wrightii, Aplopappus)
Plant Family
Dry rangelands, river valleys, and drainage areas.
Animals Affected
Horses, cattle, sheep and goats
Jimmy-weed - Isocoma pluriflora
Toxic Principle
Tremetol, a higher alcohol, is the suspected toxin, and it is similar to white snakeroot (Eupatorium rugosum). Ingetsion of 1-1.5% body weight of the green plant over several weeks will induce poisoning in cattle. tremetol is secreted in the milk of lactating animals and can induce severe poisoning in the young animal.
A perennial subshrub with a woody caudex or root stock. The stems are from 10-30 cm tall, with brown bark below, and are glabrous. The leaves are 3-7 cm long, and 1-3 mm wide, narrowly linear, rigidly erect, glabrous. The heads are few to many, with bracts imbricated in 3 or more lengths, somewhat oblong to lanceolate. The color of the disk flowers is yellowish, the pappus is brown. There are no ray flowers.
Acetone odor to the breath.
Hindlimb weakness, knuckling at the fetlocks, posterior paralysis
Remove the animal from the plant and feed a nutritious diet. Mid cases recover.
Nervous System
Severe muscle tremors, weakness, recumbency, respiratory paralysis, coma, death
Hepatic System
Central lobular necrosis detectable histologically.
Marked elevation of muscle enzymes.
Special Notes
Prevention of jimmy weed poisoning of horses and livestock is best accomplished by good range management practices to avoid overgrazing. In severely infested areas, Jimmy weed can be controlled by appropriate herbicide application as part of an integrated weed management program. References: 1.Stegelmeier BL, Davis TZ, Green BT, Lee ST, Hall JO. Experimental Rayless Goldenrod (Isocoma pluriflora) Toxicosis in Goats. 2010. 22: 570-577 2.Zalkow LH, Burke N, Cabat G, et al.Toxic constituents of rayless goldenrod.1962 J Med Pharm Chem 91:1342–1351. 3.Smith RA, Lang DG. 1998, Are there toxic and non-toxic varieties of Eupatorium rugosum Houttuyn. In: Toxic plants and other natural toxicants, eds. Garland T, Barr AC, pp. 220–222. CAB International, New York, NY. 4.Lee ST, Davis TZ Gardner DR, Stegelmeier BL Evans TJ. Quantitative method for the measurement of three benzofuran ketones in rayless goldenrod (Isocoma pluriflora) and white snakeroot (Ageratina altissima) by high-performance liquid chromatography (HPLC). J Agricultural and Food Chemistry 2009 Vol. 57: 5639-5643. 5. Schmutz EM, Freeman BN, Reed RE: Jimmyweed (Haplopappus heterophylus). In Livestock Poisoning Plants of Arizona. Edited by EM Schmutz, BN Freeman, RE Reed. University of Arizona Press, Tucson, pp 42-45 (1974).
Jimmy weed showing typical flowers.
Jimmy weed leaves