Isoetes histrix

Tracheophyta LycopodiopsidaIsoetaceaeIsoetesIsoetes histrix


A small, summer-deciduous perennial, growing from a `corm`. It prefers skeletal acidic soils that are moist or flooded in winter but experience summer drought. A poor competitor, it is most frequent on pans of bare soil over S.-facing rock outcrops, but also grows on erosion pans and footpaths. It sometimes occurs in short turf, and in dune-slacks in Guernsey. Lowland.



World Distribution

Mediterranean-Atlantic element.

© Shannon, P

Broad Habitats

Inland rock (quarries, cliffs, screes)

Light (Ellenberg): 8

Moisture (Ellenberg): 7

Reaction (Ellenberg): 5

Nitrogen (Ellenberg): 1


Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 6.6

July Mean Temperature (Celsius): 16.2

Annual Precipitation (mm): 829

Life form information

Height (cm): 4

Perennation - primary


Life Form - primary




Clonality - primary

Little or no vegetative spread

Count of 10km squares in Great Britain: 3

Count of 10km squares in Ireland: 0

Count of 10km squares in the Channel Isles: 5

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.

Atlas text references

Atlas (2d)
de Bolòs O, Vigo J
1984.  Flora dels Països Catalans, I. Introducció. Licopodiàcies-Capparàcies.
Jalas & Suominen (1972)
Bangerter EB, Cannon JFM, Jermy AC
1978.  Ferns and their allies. The Island of Mull: a survey of its flora and environment. :12.1-12.7.
Page CN
1997.  The ferns of Britain and Ireland, edn 2.
Wigginton MJ
1999.  British Red Data Books. 1. Vascular plants, edn 3.