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Dr Astrid Biddle @astridbiddle.bsky.social · 3d

The flowers were just beginning, so perhaps a week made all the difference.

Dr Astrid Biddle @astridbiddle.bsky.social · 3d

I also refound the Spike-rush, Eleocharis palustris subspecies palustris mentioned in the publication of Lewis and John, 1961. I need to a summer return visit to record the morphometrics of the flower spike. It's a co-associate!
This subspecies is data-deficient on the UK Red List.

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Dr Astrid Biddle @astridbiddle.bsky.social · 3d

The closest co-associates 2 algae, Vaucheria & Botrydium granulatum, a feature shared with the Wilstone Reservoir population.
Both benefit from being single, multinucleate cells without cross walls (coenocytic) to respond to pioneer conditions. Multicellular algae might otherwise desiccate & die.

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Dr Astrid Biddle @astridbiddle.bsky.social · 3d

To put this into perspective, at Wilstone Reservoir in 2023, following a large drawdown event, I recorded Mudwort with an occupancy of 1261 OS 1 m grid cells.
The yellow is Mudwort.

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Dr Astrid Biddle @astridbiddle.bsky.social · 3d

Dropped points where the plant was found and converted to a 1 m square presence.
It had a 259 1 m grid occupancy. If assuming at least 10 plants per 1 m grid, that would give a minimum population number of 2500!

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Dr Astrid Biddle @astridbiddle.bsky.social · 3d

A synchronous emergence of seedlings, and in some places really dense.
Germination is enhanced by submersion (exposure to hypoxic conditions). This increases the germination rate and percentage once aerobic conditions return (Phartyal, S.S., et al., 2020).

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Dr Astrid Biddle @astridbiddle.bsky.social · 3d

I wanted to look at the Mudwort (Limosella aquatica) at Port Meadow this weekend, following the report of it by @trisnorton.bsky.social
I wanted to find the Smut fungus Doassansia limosellae, which was last seen in the UK in 1929. No luck though.
Here is Mudwort in flower!
@bsbibotany.bsky.social

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Dr Astrid Biddle @astridbiddle.bsky.social · 8d

I hope you have a sample because it may be a very exciting smut. According to the literature, Doassansia is found on the petioles and appears in October. I think it was last recorded in the UK >100 years ago. bladmineerders.nl/parasites/fu...

Doassansia limosellae – Plant Parasites of Europe

bladmineerders.nl

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Dr Astrid Biddle @astridbiddle.bsky.social · 9d

Does anyone offer flow cytometry in the UK, or do I need to send samples abroad?

Dr Astrid Biddle @astridbiddle.bsky.social · 10d

I would love to find out the cytotype of R. tripartitus when it turns up in newly dug pond in a new county.
Or find out how related they are to other populations.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

Cytotypes have been studied moving from Portugal to Pannonian basin, linked to the timing of drawdown events, wildfowl migration, and meeting habitats at similar stages.
Drying habitats increases the risk of being overwhelmed by more vigorous terrestrial species when exposed.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

They flower from March to May, so if the habitat dries out too early, the plants are killed by desiccation. In countries where there is an abrupt transition from winter to summer, it fares poorly.
Our UK R. tripartitus is triploid. And on the Iberian peninsula, they are hexaploid. (Middlesex shown)

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

Thank you, I'll have a good think. I need some dosh to do more 🙂

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

Other things seen: Young Water Dock (Rumex hydrolapathum) and fringing the river was the wonderful Whorl-grass (Catabrosa aquatica), which is vulnerable on the red list.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

Seed and fly free! There are areas along the Gade which are fine, clean water places, and I hope it will find these and prosper.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

Each point is a surviving plant. The river post-restoration has been substantially narrowed, so the base map no longer makes sense.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

They face tough competition from the tall fen herbs; the riparian zone fenced and ungrazed to benefit fish and others. Elevated N in river. Water seeps from the valley side through the C. cespitosa area, towards the river, watering it, and perhaps locally giving cleaner water.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

This was a reintroduction for NE SRP.
I placed flags at all the plants I found, & out of just over 200 plants, only 2 were failing. That's an astonishing summer survival rate. Plants are of the size ready to flower & set seed next year, furnishing the downstream restoration sections with new plants.

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Dr Astrid Biddle @astridbiddle.bsky.social · 10d

Completely blown away today by how the Scarce Tufted-sedge (Carex cespitosa) was faring on the River Gade.
It was with trepidation that I entered the river. Vegetation had grown tall this summer. 2025 was one of the worst for reintroducing a wetland plant. Summer drought followed high winter water.

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Dr Astrid Biddle @astridbiddle.bsky.social · 13d

I think it was rather jumbled together, and I thought it unwise to climb on board.

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Dr Astrid Biddle @astridbiddle.bsky.social · 14d

A mere ten days ago I was at the 17th International Symposium on Aquatic Plants in Lisbon. Here on the field trip:
A Cladium Mariscus Saw Sedge floating mat in the River Sado, topped with Salix atrocinerea. Other species were Royal Fern (Osmunda regalis), and Marsh Fern (Thelypteris palustris).

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Dr Astrid Biddle @astridbiddle.bsky.social · 17d

I was looking through my photos from Porto from earlier this year.
Strapwort (Corrigiola litoralis) had been looking very fine. It grew with Coral-necklace (Illecebrum verticillatum) on a path with a seepage running across it. What a lovely plant!

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Dr Astrid Biddle @astridbiddle.bsky.social · 17d

Fenland preparing for winter. Whorled Water-milfoil (Myriophyllum verticillatum) forming dense, dark-green turions which will keep the plant safe in the cold.

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Dr Astrid Biddle @astridbiddle.bsky.social · 17d

Solanum revealed 2 species: nigrum & nitidibaccatum, Black & Green Nightshade. Apart from the obvious berry colour, it always remained possible that Green Nightshade could have been unripe berries.
Green= sepal lobes expand as the berries mature
Black= stays the same

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Dr Astrid Biddle @astridbiddle.bsky.social · 17d

This wasn’t growing as a freshly exposed arable seedbank as an arable weed, but on soil which was the result of the recent ditch clearance. This was one of the Fenland winners.
Was the seed stored in the silt, once farmland soil?
Perhaps it had just exploited the bare soil after disturbance?

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