Description: The common name of this species refers to the three-lobed or trifid nature of the leaves. (It has nothing to do with the triffids of John Wyndham's classic science-fiction story!) It produces rayless flower-heads similar to those of Bidens cernua var. cernua and occurs in fens, marshes and lakeshores, often growing alongside that species. It is mainly found about Lough Neagh, Lough Erne and the Co. Down lakes.

All names: Bidens tripartita L.; Bidens peacockii Druce

Distribution Map from NBN: Bidens tripartita at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Bidens tripartita at iNaturalist World Species Observations database.