This plant belongs to the family of Asteraceae. Groundsel are widespread over the world and represented with more than 1000 different species. For Senecio pyrrolizidin alkaloids are typical, which are mainly known to be hepatotoxic and cancerogenic.
Senecio riddellii occurs in the southwest of the United States, mainly Texas, New Mexico and Arizona. It contains the pyrrolizidin alkaloids Riddelliine and its N-oxide. Riddelliine can be found as a contaminant in foods such as meat, grains, seeds, milk, herbal tea and honey.
The results in research about adverse health effects of pyrrolizidine alkaloids like Riddelliine, made it necessary to have reliable reference standards for food and feed safety.
Am J Vet Res. 1991 Jan;52(1):146-51. Toxicity of pyrrolizidine alkaloids from Riddell groundsel (Senecio riddellii) to cattle. Molyneux RJ1, Johnson AE, Olsen JD, Baker DC.