horned butterwort

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.

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.

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.