Groundsel (Senecio vulgaris
) is an erect herbaceous, winter annual that is considered an invasive weed in many regions. It starts to germinate in late autumn through early spring, matures throughout the spring and dies early summer due to the summer heat. When S. vulgaris
first emerges, it the first couple leaves may have purple on the underside with shallow teeth, and are attached to the stem with a short petiole. As it matures, the leaves become more deeply lobed and attach directly to the stem. The leaves of the plant alternate on the stem and are usually hairless. S. vulgaris
produces open clusters of small bright yellow, cylinder-shaped, rayless flowers that mature into a ball of white-tufted seeds. Flower clusters are surrounded by green bracts with black tips.
All parts of S. vulgaris
contains pyrrolizidine alkaloids, which can cause pyrrolizidine alkaloid toxicity
in horses, if ingested over a period of time. Previous cases of poisonings usually occur due to the accidentally presence of S. vulgaris
in the horses' hay. Symptoms don't begin to present until after damage occurs to the horse's liver, from chronic ingestion of the plant.