logo Calflora, a 501c3 non-profit
Taxon  Report  
Pinguicula macroceras  Link
California butterwort
Pinguicula macroceras is a perennial herb (carnivorous) that is native to California, and also found elsewhere in North America and beyond.
California Rare Plant Rank: 2B.2 (rare, threatened, or endangered in CA; common elsewhere).
Siskiyou Del Norte Modoc Humboldt Shasta Lassen Trinity Plumas Tehama Butte Mendocino Glenn Sierra Yuba Lake Nevada Colusa Placer Sutter El Dorado Yolo Alpine Napa Sonoma Sacramento Mono Amador Solano Calaveras Tuolumne San Joaquin Marin Contra Costa Alameda Santa Cruz Mariposa Madera San Francisco San Mateo Merced Fresno Stanislaus Santa Clara Inyo San Benito Tulare Kings Monterey San Bernardino San Luis Obispo Kern Santa Barbara Ventura Los Angeles Riverside Orange San Diego Imperial
Observation Search
(80 records)
yellowone or more occurrences
within a 7.5-minute quadrangle

Bloom Period
Genus: Pinguicula
Family: Lentibulariaceae  
Category: angiosperm  
PLANTS group:Dicot
Jepson eFlora section: eudicot

Wetlands: Occurs in wetlands

Ultramafic affinity: 6 - strict endemic

Habitat: bogs/fens

Communities: Freshwater Wetlands, wetland-riparian

Name Status:
Accepted by JEF + CNPS + PLANTS

Alternate Names:
JEFPinguicula macroceras ssp. macroceras
JEFPinguicula macroceras ssp. nortensis
JEF + CNPSPinguicula vulgaris ssp. macroceras
Information about  Pinguicula macroceras from other sources
Nursery availability from CNPLX
Commercial availability unknown.
Jepson eFlora


Photos on Calflora

Photos on CalPhotos

Google Images

Photos on iNaturalist

ID Tips on PlantID.net

[Wikipedia] Description, Habitat, Distribution, Ecology: Pinguicula macroceras, the California butterwort[1] or horned butterwort, is a species of perennial carnivorous herb that is native to the North American Pacific coast, as well as other select distributions in Canada, Russia, Japan, and the United States.[3] [7] Common names include California butterwort, horned butterwort and butterwort. Pinguicula macroceras belongs to the genus Pinguicula and the family Lentibulariaceae. Description Pinguicula macroceras is a carnivorous perennial herb growing less than 20 cm tall.[3] With simple fleshy leaves (green-dark brown) that form a basal rosette, that are often recognized as slimy or sticky, and occasionally incurving over trapped prey.[3] The leaves are adaxially glandular with stalked glands for capturing small organisms and sessil glands for the digestion of their prey.[3] A single rosette can have 1-5 inflorescences held up by individual stems, which are composed of a single purple-blue flower (rarely observed with 2) that lack bracts.[3] The calyx upper lip of the flower is 3-lobed, while the lower lip is 2-lobed with the center colored white.[3] The corolla measures 13?21 mm with a lip that is often found to be hairy and generally does not block the throat of the flower.[3] The flowers form a distinct horn on the top, hence the common name horned butterwort. Habitat Pinguicula macroceras are found growing in moist habitats and often in serpentine conditions.[3] Moist slopes and serpentine banks along creeks and rivers, at an altitude less than 1800 m are places where they are likely to be located.[4] Serpentine cliff sides (most often north facing) with fast flowing seeps have also been documented habitat of the Pinguicula macroceras.[4] Moist habitats that are home to Pinguicula macroceras are often dominated by layers of moss that they form basal rosettes on top of and bury their roots underneath. Distribution In North America P. macroseras is found within 750 km of the Pacific coast in California, Oregon, Washington, and into Canada.[1] [7] Other populations of P. macroceras are known to exist in Russia and Japan.[3] Disputes over the classification of P. macroceras as a species rather than a sub-species of P. vulgaris along with the difficulties of distinguishing the two species from each other have made defining the distribution of P. macroceras difficult in areas where the species are sympatric.[2] Ecology Pinguicula macroceras - growing on moss covered cliff side in Hiouchi, California. Pinguicula macroceras exists in an ecological niche that is unsuitable for most other types of plant life with some exceptions e.g. moss. They have done this by growing in water abundant, nutrient deprived serpentine soils and cliff sides, adopting a carnivorous behavior to supplement the nutrients that are absent in the serpentine habitats. (contributed by Mary Ann Machi)

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals. [web application]. 2023. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 12/11/2023).