There are several large plants, most of which prefer moist environments, with umbels (inflorescence in which the stalked flowers all arise from a single point) of white flowers. These “giants” look very similar and are often difficult to distinguish from each other. Ranger’s buttons (Sphenosciadium capitellum) at first glance is also a large plant with white umbels. However, it is easy to identify because the umbel is composed of small flowers arranged on well-separated umbellets that resemble small fuzzy balls.
Sphenosciadium is a monotypic genus, meaning that there is only one plant in the genus, ranger’s buttons. This genus name comes from the Greek “sphen” meaning wedge and “sciados”, an umbrella. The name refers to the wedge-shaped fruits and umbrella-shaped umbel of ranger’s buttons. The species, capitellum, is Latin for “having a small head” like the button-like umbellets. Button parsley, swamp white heads and woollyhead parsnip are other colloquial names for ranger’s buttons.
A member of the Carrot Family, ranger’s buttons are a native perennial found in California, Oregon, Nevada and Idaho up to about 9,000 feet elevation. Their habitat is streams, marshes, lakes and other moist places.
Ranger’s buttons has an erect stem that arises from a tuber. The stem can reach up to 5 feet in height and is smooth. The large leaves are pinnately divided into narrow, well-spaced, sparsely toothed or irregularly cut leaflets. The leaf petioles are swollen and sheathed around the base of the stem.
The inflorescence of ranger’s buttons is a compound umbel. Each umbel has 4 to 18 (usually 9) umbellets composed of tiny, white flowers that form a dense ball. The protruding stamens of the tiny flowers make the umbellet appear fuzzy. There are bristly bracts between the flowers. Although the ranger’s button stem is smooth, the rays of the umbel are bristly with rough hairs.
Ranger’s buttons fruits are wedge-shaped, tomentose (hairy) and compressed front to back with wide, lateral wings.
Ranger’s buttons plants contain furanocumarins and are toxic to livestock and humans, causing serious, ulcerative photosensitivity, cloudy corneas and blindness. Infusions of the roots were used by Native Americans to treat lice and venereal sores.
These ranger’s buttons were growing in Lassen Volcanic National Park near the Hat Creek Trailhead (Lassen County CA) last August.