Sunday, 21 August 2016

Ray's Knotgrass on Sidmouth Beach

I would never have imagined that I'd see a new plant species in Sidmouth and certainly not on the beach where there is very little vegetation to speak of, just a couple of very small patches. Yesterday though I received an e mail from Steve at ND&B telling me that he had been visiting Sidmouth while on holiday and had seen what looked like Ray's Knotgrass on the beach. He hadn't had chance to examine it though and suggested I go and take a look. I went down there today and indeed it was! There were two nice clumps right at the top of the beach near the path around to Jacob's Ladder. There are no previous records of it in Sidmouth that I know of but it has been seen further east at Weston Mouth and Salcombe Regis Beach. I've previously seen Sea Knotgrass on Hayling Island which is much rarer than Ray's but looks very similar, the differences are quite small. The stipules being conspicuous, longer than upper internodes and silvery with many veins on Sea Knotgrass while on Ray's Knotgrass they are shorter than internodes brownish in colour and silvery just at the tips. The seeds are slightly larger in Sea Knotgrass too and in both of these rare species they protrude above the top of the flower. Both species also have fleshy leaves which are more glaucous in Sea Knotgrass and in-rolled.

Ray's Knotgrass - Polygonum oxyspermum
Note: Small stipules green/brown in colour and a few slightly in-rolled leaves.

Sea Knotgrass - Polygonum maritimum
(Hayling Island Hants 2015) 

Note: Very conspicuous white stipules, longer than internodes with many veins and glaucous leaves heavily in-rolled.

Also today I spent a while watching a single Black-tailed Godwit feeding on Ragworms, I can still take photos of birds too!


Steve Gale said...

Thanks for going along to check them Karen. Only the second time that I've recorded this species!

Andrew Cunningham said...

Thanks Steve and Karen, I think I will twitch this later this week.

John Twibell said...

Thanks for this Karen, We knew that there was a knotgrass on the site, but hadn't determined species. There are many plants this year along the edge of the pathway and in the "Beach Garden" itself. It is one of the species already on the site and not one of the rarities that we have been planting in our conservation area. It may be worth informing potential visitors (as on our display board at the site) that Sidmouth in Bloom together with Devon Plant Heritage and EDDC are using this part of the beach as a conservation area to grow endangered local coastal plants from fragile dune, shingle and saltmarsh habitats.
John Twibell, Sidmouth Beach Garden

Karen Woolley said...

John - Thanks for commenting. There is also Common Knotgrass on the site and lots of it.