Widehead groundsel (Packera eurycephala) is a native perennial formerly identified as Senecio eurycephala. The current genus name honors Botanist John George Packer (1929 – 2019) who was a specialist on Arctic and alpine flora and taught at the University of Alberta in Canada. The species designation is from the Greek and means wide head – eury or eurys/wide or broad and kephale/head.
This Asteraceae Family (Sunflower Family) member has numerous branching stems arising from a woody caudex (root stock). The deeply lobed leaves are alternate with most leaves crowded in the basal part of the plant. The cauline (stem) leaves are gradually reduced in size and number of lobes. As a consequence, the flower stalks often look naked. All the herbage is covered with densely matted, woolly hairs. Lobeleaf groundsel is another common name for this plant.
The flower heads occur singly or in arrays at the end of the stems and are composed of yellow ray and yellow disk flowers. The 8 to 13 rays are lightly toothed at the end. There are many tightly packed, fertile disk flowers. The flower heads are surrounded by a single series of green or yellowish, pointed phyllaries.
Widehead groundsel seeds are achenes with a pappus of many, soft white bristles.
Found in Oregon, Nevada and California, widehead groundsel grows in dry, open places between 1,500 and 5,000 feet. These widehead groundsel plants were photographed along a logging road in Widow Valley near Lookout CA (Modoc County) in June.