Juncus trifidus

Tracheophyta MagnoliopsidaJuncaceaeJuncusJuncus trifidus


A small, densely tufted perennial herb found in bare or bryophyte- or lichen-rich places on mountains on shallow soil or in rock crevices, on both acidic and calcareous substrata. J. trifidus is one of the principal angiosperms of wind-swept, often almost snow-free plateau edges over c. 1000 m, but it also occupies sites that are snow-covered for several months. From 240 m on Ronas Hill (Shetland) to 1310 m in the Cairngorms.



World Distribution

Eurosiberian Arctic-montane element; also in N. America.

© Pete Stroh

Broad Habitats

Montane habitats (acid grassland and heath with montane species)

Light (Ellenberg): 8

Moisture (Ellenberg): 5

Reaction (Ellenberg): 2

Nitrogen (Ellenberg): 2


Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 1

July Mean Temperature (Celsius): 11.5

Annual Precipitation (mm): 2162

Life form information

Height (cm): 30

Perennation - primary


Life Form - primary




Clonality - primary

Tussock-forming graminoid, may slowly spread

Count of 10km squares in Great Britain: 177

Count of 10km squares in Ireland: 0

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: -0.38

Distribution information

JNCC Designations


PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.