Equisetum variegatum

Tracheophyta EquisetopsidaEquisetaceaeEquisetumEquisetum variegatum

Ecology

An evergreen, prostrate herb found in a wide variety of habitats, including dune-slacks, river shingle, upland flushes and stony loch-shores. It is a calcicole and a poor competitor; its sites are usually open and often winter-flooded. In Ireland a more vigorous, upright ecotype is found mostly on canal banks. 0-1040 m (Ben Lawers, Mid Perth).

Status

Native

World Distribution

Circumpolar Boreo-arctic Montane element.

Broad Habitats

Fen, marsh and swamp (not wooded)

Light (Ellenberg): 8

Moisture (Ellenberg): 8

Reaction (Ellenberg): 8

Nitrogen (Ellenberg): 3

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 3.4

July Mean Temperature (Celsius): 14

Annual Precipitation (mm): 1224

Height (cm): 60

Perennation - primary

Perennial

Life Form - primary

Non-bulbous geophyte (rhizome, corm or tuber)

Comment on Life Form

rhizomatous geophyte with wintergreen stems

Woodiness

Herbaceous

Clonality - primary

Rhizome far-creeping

Count of 10km squares in Great Britain: 170

Count of 10km squares in Ireland: 129

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: -0.12

JNCC Designations

NHMSYS0000458478

Scarce Atlas Account

Scarce Atlas Account: 

Equisetum variegatum Schleicher

Variegated horsetail

Status: scarce

 

 

This is a plant of a wide variety of open habitats, ranging from sand dune slacks at sea-level to mountain ledges. The species frequently dominates the lowest and most frequently flooded areas of dune slacks. At middle altitudes it can be found on river gravels and in many upland sites it is associated with flushes and calcareous springs. All sites are base-rich to some extent, and characteristic associates include Carex capillaris, C. flacca, C. viridula subsp. brachyrryncha, Saxifraga aizoides, Selaginella selaginoides, Cratoneuron commutatum, Ctenidium molluscum, Philonotis calcarea and Scorpidium scorpioides. It ascends to at least 1040 metres on Ben Lawers. 

Established plants spread by rhizomes. Populations in all sites produce cones readily and gametophytes could presumably colonise nearby open habitats.

There is little evidence of a decline and it is probably still present in many of the upland 10 km squares for which only pre-1970 records are available.

This is a northern montane species, scarce or scattered in the Baltic basin but frequent in the Pyrenees and the central European mountains (Jalas & Suominen 1972). It is found in mountainous areas across Asia to northern Japan, and through northern North America south to Pennsylvania and in the Rockies to Colorado.

E. variegatum is variable morphologically as well as physio-ecologically and both coastal populations and those of mountain streamsides and ledges should be conserved.

 

 

A. C. Jermy

Atlas text references

Atlas (3c)
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
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.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.