Information on Mare's-tail

Common Name: Mare's-tail
Scientific Name: Hippuris vulgaris
Irish Name: Colgrach
Family Group: Plantaginaceae
Distribution: View Map (Courtesy of the BSBI)
Flowering Period

Click for list of all flowering by month
Mare's-tail is not easily confused with other wild plants on this web site.

In still and slow-flowing water and at the margins of lakes, Mare’s-tail is an aquatic species which grows on rhizomes. It has stems which are stout, round, spongy and erect and they bear shiny, narrow, strap-shaped, dark-green leaves in whorls of 6-12. At the base of each leaf is a very tiny, solitary, greenish flower. There are no petals or sepals and a plant can often bear both male flowers – with one reddish anther – and female flowers – with a single white style. The flowers can be seen – best with a hand lens – in June and July. The fruit is a tiny, green nut.  Mare’s-tail is a perennial, native plant which seems to be found more in the northern two-thirds of Ireland than the southern. It shows up to 1 metre of itself above the waterline. When it grows in mud, it is generally a good bit smaller. It belongs to the Plantaginaceae family. 

I first saw this species growing at the edge of the King’s Bog in Co Kildare in 2011 when I also photographed it. 

If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre

Mare’s-tail is a totally different species to a genus commonly known as Horsetail. Horsetails belong to the Equisetaceae family which reproduce by spores rather than seeds. A lot of confusion seems to arise because of their common names being so similar.