Packera

Packera is a genus of flowering plants in the aster family (Asteraceae). These plants are commonly known as groundsels or ragworts, although the common name "ragwort" is more frequently associated with the species Jacobaea vulgaris (formerly Senecio jacobaea). The genus comprises herbaceous perennial plants, some of which are native to North America and others to Eurasia.

Packera species were previously classified within the large genus Senecio. However, phylogenetic studies based on molecular data revealed that Senecio was not monophyletic, and a number of species were segregated into the newly redefined genus Packera.

Packera species are characterized by their yellow, daisy-like flowers arranged in clusters (corymbs or panicles). The leaves are often deeply divided or lobed, and the stems are typically erect. Packera plants are often found in a variety of habitats, including meadows, woodlands, and disturbed areas.

Several species of Packera contain pyrrolizidine alkaloids, which can be toxic to livestock, particularly horses and cattle, if ingested in large quantities. These alkaloids can cause liver damage and other health problems.

Some notable Packera species include:

• Packera aurea (Golden Ragwort)
• Packera obovata (Roundleaf Groundsel)
• Packera plattensis (Prairie Ragwort)

The taxonomy of Packera and related genera in the Asteraceae family is complex and has been subject to ongoing revision based on new molecular data.