A native of Western United States and found in the western and many central states (except New Mexico), western groundsel (Senecio integerrimus) grows in mountain meadows, on montane talus slopes and is especially prevalent in the sagebrush communities of Northeastern California. These western groundsel plants were photographed in our north pasture in Modoc County CA, the northeast corner of the state.
A variable plant derived from a shallow, fibrous root system, western groundsel has a single stout, erect stem with several small yellow flower heads borne at the tip of the stem. The flower head is composed of both disc and ray flowers, as are the flowers of other members of the aster (or sunflower) family. Black-tipped bracts surround the flower heads. The lance-shaped basal leaves are somewhat succulent and have a petiole (leaf stalk). Proceeding up the stem the leaves are stalkless and get smaller. Young plants have masses of white hairs which are lost as the plant matures. The achene (small, dry, single seeded fruit) is topped with a white pappus (hairs or bristles).
Western groundsel usually grows to a height of one or two feet. However, in drier areas it may not reach more than 6″ in height.
Western groundsel, also called tower butterweed, contains poisonous alkaloids and could potentially be dangerous to livestock. Though due to its unpalatability livestock poisoning rarely occurs. It can also be a contaminant in fields (especially in Oregon and Washington) and thus is often considered a noxious weed rather than a wildflower. Because of the alkaloid content, western groundsel has minimal medicinal use.
The genus name, Senecio, is from the Latin “senex” meaning “old man”. This might refer to the white hair on the leaves and stem or perhaps the fluffy white pappus (hairs) on the seed.