IWoodward's picture

Whorled aquatic plant - Mare's-tail?

Observed: 7th October 2012 By: IWoodwardIWoodward’s reputation in PlantsIWoodward’s reputation in PlantsIWoodward’s reputation in PlantsIWoodward’s reputation in Plants
Woodford Golf course whorled plant 2012-10-07 2
Woodford Golf course whorled plant 2012-10-07 1

In mud at edge of pond

Species interactions

No interactions present.


markwilson's picture

If I am correct make sure you

If I am correct make sure you do not introduce this to other ponds it is very invasive and spreads readily from fragments

IWoodward's picture

Thanks Mark, but...

I don't think it's Crassula helmsii as I've never seen this species with leaves in whorls of 6-8, and it doesn't have any rings below the nodes like C. helmsii. As you say though some plants can be very variable in different conditions, so it's possible you may be right.

Sadly crassula helmsii IS definitely present at the pond (more typical specimens), along with the arguably even more invasive Floating Pennywort. I've already contacted the site owners who are aware of the problems associated with both species and the difficulties in dealing with them.

markwilson's picture

Yes I see what you mean about

Yes I see what you mean about lf whorls can't think of anything esle at moment - will let you know if I have any bright ideas - I have never seen small mare's tails like this though

Rachy Ramone's picture

Sure it's an aquatic?

Looks rather like a Galium to me.... if it's marginal and the level has risen, could it be one of the bedstraws? (Galium verum for choice)

Not an expert on pond plants....

Rachy Ramone

How to take close-ups with cheap phone and hand-lens:
Field Guides for Budding Botanists:

IWoodward's picture


It was in mud at the pond edge so it is possible it isn't an aquatic.

Galium was actually my first thought but close examination of the leaves showed no prickles on the edges which rules out most Galium species, and a smooth round stem which should rule out G. verum - though it could be an atypical example of G. verum and the size certainly fits.

I haven't yet had a chance to check out lavateraguy's suggestions but an aquarium throw out seems the most likely option to me.


IWoodward's picture


Having spent some time looking at options online, I've been back to look at the plant again today and am still none the wiser. I think lavateraguy's ID is probably correct but I wasn't able to narrow it down any further. Hydrilla verticillata seems the best fit but I looked closely and could see no sign of the minute scales at the base of the leaves mentioned in Stace. Some photos of Lagarosiphon on the internet also look very like my plant.

Thanks for all your suggestions. I'll keep an eye on it in the hope that I can solve the mystery in the future.


lavateraguy's picture

Egeria densa

Since you've encouraged me to think further on the question, did you consider Egeria densa, which has about 30 British records. Egeria differs from Elodea in having leaves in whorls of 4 or more, rather than whorls of 3.

IWoodward's picture

Egeria densa

Thanks for adding this extra suggestion. However I did look at E. densa and it was another one that looked possible but didn't tick all the boxes in Stace and Poland/Clement.

Most of the photos i've found of the Hydrocharitaceae are of plants growing underwater, so I'm not sure which (if any) would grow at the water's edge and how their appearance would vary as a result. I also still have entirely ruled out the possibility of an atypical Galium verum, as suggested by Rachy Ramone.

Maybe I need to wear wellies next time and check to see if there are any specimens growing underwater!