This is the hybrid between Equisetum fluviatile (Water Horsetail) and Equisetum telmateia (Great Horsetail) both of which are common horsetails. According to Stace this hybrid is also an endemic. It has characteristics of both parents with a large size (up to 60 or 70 cm tall) and the dense branching habit of E. telmateia with a very large hollow in the centre of the stem like E. fluviatile. The obvious question is if the two parents are so common why are there very few records of the hybrid?

Answer: Don't know but it is only known so far from sites in Cornwall and West Lancashire and so is listed as vulnerable.

West Lancashire 7th June 2007

Added on 26th June 2007, updated 2nd January 2009, updated 29th March 2010