Yesterday there was a field meeting on the Pevensey Levels. However, Viola and I got to the meeting point just a little late and everyone had already set off. The guys fishing nearby indicated which way the group had gone, but we couldn’t find them, and as we were deliberating what to do next, Jo and Julian arrived.
Realising that we weren’t going to find the participants of the actual field meeting, we decided to have a clandestine excursion ourselves and explore some ditches. Though we didn’t produce a very long species list, it ended up being an excellent and interesting day out. In the absence of any water-plant specialists we sat in the sun and keyed everything out, and learnt a lot in the process. It was also a day of two very different ditches, one in TQ60I and the other in TQ60D.
The larger, emergent plants were easy to identify, and included Hydrocharis morsus-ranae (Frogbit), Sagittaria sagittifolia (Arrowhead), and Rumex hydrolapathum (Water Dock).
Mercifully, Jo and Julian had brought a grapnel, so getting hold of some of the other plants wasn’t too hard, even if identifying a couple of them took a little longer.
Most abundant from our first sampling point was Potamogeton pectinatus (Fennel Pondweed), though it was the one that it took us longest to key out, using a combination of David Streeter’s Collins Flower Guide, Chris Preston’s BSBI Handbook, and Nick Stewart’s handouts which Jo had.
The second sampling point just 10m from the first had abundant Potamogeton lucens (Shining Pondweed), one that we recognised from last year’s field meeting to Pevensey (though still keyed it out to make sure).
Finally, the other aquatics there were Ceratophyllum demersum (Rigid Hornwort) and Elodea nuttallii (Nuttall’s Waterweed), which kept us busy through lunch as well.
Heading a little bit west we crossed into the next tetrad and found a very different-looking ditch, which occupied us for the rest of the afternoon. Most prominent was Sparganium erectum (Branched Bur-reed) and Alisma plantago-aquatica (Water Plantain), together with a considerable peppering of Lemna trisulca (Ivy-leaved Duckweed).
Also growing in the water were a few plants of Oenanthe fistulosa (Tubular Water-dropwort) and Apium inundatum (Lesser Marshwort), the latter new to the tetrad.
There were also several clumps of Veronica catenata (Pink Water-speedwell) in this part of the ditch.
The muddy edges of the ditch also revealed a few extra species, including Carex otrubae (False Fox-sedge), Ranunculus sceleratus (Celery-leaved Buttercup), and Samolus valerandi (Brookweed), the latter also a new tetrad record.
Two other aquatics were also lurking here. Julian extracted another Potamogeton, this time another one that we saw last year, and a rare species, Potamogeton acutifolius (Sharp-leaved Pondweed).
Interestingly, one of the most abundant plants here was a charophyte, which appears to be Chara vulgaris (Common Stonewort), judging from its corticate, infrequently-spiny stem, blunt stipulodes in pairs, and the spines appearing to come out of the stem furrows.
So, not quite the day any of us had expected, but terrifically interesting, and lots of fun. I wonder what everyone on the actual field meeting found?
21 June 2017: The actual field meeting report is now available.
 See Nick Stewart’s Key to Common Species of Stonewort, available at http://bsbi.org/identification, and Jacek Urbaniak and Maciej Gąbka Polish Charophytes: An Illustrated Guide to Identification (Wrocław, 2014), available from: https://www.researchgate.net/publication/273754931_Polish_Charophytes_An_illustrated_guide_to_identification