California butterwort (Pinguicula macroceras) is a carnivorous or “insect eating” plant. It is found in fens, bogs, swamps, mossy seeps, rocky drip faces and moist serpentine banks – habitats with low available nitrogen – in Alaska, British Columbia, Washington, Oregon, Idaho, Montana and California as well as Russia and Japan. In California it is considered a rare plant because of its limited range.

A native perennial, California butterwort has a basal rosette of leaves that arise from fibrous roots. The greenish-yellow, fleshy leaves have smooth edges and are sticky on the upper surface. When an insect lands on and sticks to a leaf the edges inroll.  The leaf then secretes juices that digest the soft tissue of the insect, thus providing nutrients to the plant.

One to five scapes (leafless flower stalks) arise from the basal rosette of leaves. Atop the scape is a single, lavender, violet-like flower with two lips. The upper lip has 2 lobes and the lower lip has 3 lobes. There is a long, backward-projecting spur. The flower throat is white and there are white hairs in the throat.

California butterwort fruits are round capsules with 2 or 4 valves which burst irregularly and contain several seeds.

Also colloquially called horned butterwort or common butterwort, P macroceras has a confused taxonomical history. Originally considered part of Pinguicula vulgaris, California butterwort is now considered distinct enough to merit its own species designation. However, range is often used for identification. Pinguicula vulgaris macroceras is another designation for California butterwort.

Pinguicula is from the Latin “pinguis” meaning fat. The genus name refers to the succulent, sticky or greasy leaves. The species name comes from Greek and describes the spur: “macro” is large and “keras” is horn.

Butterworts supposedly encouraged the production of milk in cows which would then insure a good supply of butter giving these plants their common name (wort means plant). In England the udders of cows would be rubbed with the juice of butterwort species. Butterworts were also thought to protect humans from witches and fairies.

These California butterworts, members of the Bladderwort Family, were growing along Howland Hill Road in Jedediah Smith Redwoods State Park (Del Norte County CA),