Mackay's Horsetail

MACKAYS HORSETAIL
(EQUISETUM TRACHYODON)

LOCAL BIODIVERSITY ACTION PLAN

Links to associated HAPs

Coastal Sand Dune

Ecology

Appearance

Stems grow up to 100 cm high and be 2-6 mm diameter.

Mackay's horsetail (Equisetum x variegatum) is a hybrid of Variegated horsetail and Dutch horsetail and is only found on a couple of sites in the UK. The stems of the plant are usually unbranched although often have an odd branch which are found very low down and so look like a separate stem. The stems have rough ribs each with 2 rows of tiny tubercles. The sheaths have both teeth and hair-points, which during winter fall together.

The number of stem ribs or sheath teeth is usually between 7 and 13. The cone of the plant and looks like that of Variegated horsetail but is sterile and so is less developed and often remains partly included in the top sheath. The sheath is pale green or grey with a black band at the top, eventually turning entirely black. The teeth have a black centre with pale edges and may also turn wholly black.

Habitat
MacKay's horsetail prefers coastal areas.

Current Status

This species, a sterile hybrid of rough horsetail and variegated horsetail, occurs in three sites in the Cheshire region, Red Rocks Marsh Nature Reserve and Royal Liverpool Golf Course at Hoylake, and Wallasey Golf Course, all on the Wirral peninsula. The species has been lost from a site in Meols but a substantial population was found a couple of years ago along a footpath south of Hoylake station. Nationally, the species occurs locally in two dozen locations in Ireland and five in Scotland but no other sites in England.

It thrives particularly in sites where competition from other species is low and especially where this state is maintained by surface erosion or continual addition of wind blown sand.

Threats
* Habitat loss to coastal accretion - it is not clear whether this natural change will provide new good habitat or not.
* Habitat loss to cycleway
* Open Golf Championship at Royal Liverpool Golf Course, 2006.

Objectives, Targets and Actions

Objectives, targets and actions to help conserve mackays horsetail in the Cheshire region can be found on the Biodiversity Action Reporting System (BARS) along with full details of our progress so far.

How to find out more about Mackay's Horsetail

Contact Christine Smyth on 0151 666 4730

Contact details
LBAP Chair Hilary Ash
Phone: 0151 327 5923

References & Glossary
Page, C. N.: The Ferns of Britain and Ireland, 2nd edition.
Page, C. N.: A Natural History of Britains Ferns, New Naturalist Series
http://www.plant-identification.co.uk/skye/equisetaceae/equisetum-x-trachyodon.htm