Pinguicula macroceras
Horned butterwort, Horned Butterwort
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Family: Lentibulariaceae · Type: Herb · Native
Conservation status: CNPS 2B.2
Pinguicula macroceras (Horned butterwort) is a native California herb in the Lentibulariaceae family, recognized by California represents southern range limit - genus primarily circumboreal, this species mainly Alaska to Oregon.
Horned butterwort is a rare (CNPS 2B.2) California native perennial found in northern Klamath Ranges in Del Norte and Siskiyou counties, growing on moist slopes, cliffs, and serpentine banks at elevations below 1,830 meters. Flowering from April to July, this distinctive plant produces pale blue-violet flowers with a white center, each blossom 13 to 21 millimeters long with a delicate 6 to 9 millimeter spur. Growing with low-spreading rosettes, it forms compact clusters of 1 to 5 flower stalks reaching 10 to 20 centimeters tall. Its leaves are 2 to 5 centimeters long, elliptic to ovate, ranging in color from green to dark brown with a distinctive carnivorous adaptation. The flower's lower lip is notably hairy, with obovate lobes creating an intricate botanical structure.
Identification and appearance
Key characters: California represents southern range limit - genus primarily circumboreal, this species mainly Alaska to Oregon
Habitat and range
Habitat: Moist slopes, cliffs, serpentine banks
Elevation: < 1830 m
California counties: Del Norte, Humboldt, Siskiyou
Outside California: southwestern Oregon, also northern Oregon to Alaska, Russia, also Japan
Bloom period
Pinguicula macroceras blooms Apr-Jul.
Conservation status
CNPS 2B.2
How to tell it apart
vs Utricularia: Pinguicula has sticky rosette leaves on land, while Utricularia is aquatic with finely dissected parts.; vs Proboscidea: Pinguicula has simple smooth-edged leaves, while Proboscidea has large lobed leaves and distinctive curved seed pods.; vs Mimulus: Pinguicula has greasy sticky leaves, while Mimulus has normal-textured leaves without stickiness.; vs Limosella: Pinguicula has blue-violet spurred flowers, while Limosella has tiny white bell-shaped flowers.; vs Synthyris: Pinguicula has sticky carnivorous leaves, while Synthyris has normal non-sticky leaves.
Frequently asked questions
Is Pinguicula macroceras native to California?
Yes. Pinguicula macroceras is native to California (recorded as native).
When does Pinguicula macroceras bloom?
Pinguicula macroceras blooms Apr-Jul.
Where in California does Pinguicula macroceras grow?
Pinguicula macroceras occurs in Del Norte, Humboldt, Siskiyou, at elevations of < 1830 m.
What plant family does Pinguicula macroceras belong to?
Pinguicula macroceras is in the Lentibulariaceae family, genus Pinguicula.
Is Pinguicula macroceras rare or endangered?
Pinguicula macroceras carries California Rare Plant Rank 2B.2, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.