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Dr Astrid Biddle

@astridbiddle.bsky.social
981 followers 981 following 1.5K posts

Senior Plant Ecologist Freshwater Habitats Trust BSBI Recorder for Buckinghamshire. BBS Joint Recorder Herts. Views my own.❤️Aquatic plants & many others.

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Dr Astrid Biddle @astridbiddle.bsky.social · 11/10/2026
It looks like a population which is producing lots of flowers & likely lots of seed to replenish its seedbank. Compare with last year's Port Meadow population, where it was hard to find a single flower. Yet not quite as prolific as the population I found in Spain. Episodic species are fascinating!
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Dr Astrid Biddle @astridbiddle.bsky.social · 04/10/2026
If not, then Fool’s Watercress (Helosciadium nodiflorum) that it lacks bracts:
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Dr Astrid Biddle @astridbiddle.bsky.social · 04/10/2026
The leaves appear to have the vicious teeth of Lesser Water-parsnip (Berula erecta). I can't see if it has bracts and bracteoles but it should look like this:
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Dr Astrid Biddle @astridbiddle.bsky.social · 04/10/2026
An absolutely stunning place to be in the last days of September.
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Dr Astrid Biddle @astridbiddle.bsky.social · 04/10/2026
@wildflowerhour.bsky.social Still flowering this week: Seaside Centaury (Centaurium littorale) at the edge of a dune slack pond near Southport.
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Dr Astrid Biddle @astridbiddle.bsky.social · 04/10/2026
Dipped into Hatchet Pond this week to see what charophytes were there: stands of Nitella transluscens out beyond the Myriophyllum alterniflorum. In a hidden corner, a strand of Utricularia minor.
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Dr Astrid Biddle @astridbiddle.bsky.social · 03/10/2026
Hopefully, we'll be publishing my results for this pond set. And the Nitella! Is it a long-lived spore bank in the soil, or is it species mobility at the landscape scale? I feel so sad that autumn is with us now. I didn't want this year to end. So much to see! @bsbibotany.bsky.social
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Dr Astrid Biddle @astridbiddle.bsky.social · 03/10/2026
My last official plant survey of the season today. The last of the over 140 ponds I visited in England, from Cornwall to Northumberland. Here, finally in Bucks, I ended with Nitella flexilis agg. Another plant, & another new area record. My 4th record for this species in this county this year.
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Dr Astrid Biddle @astridbiddle.bsky.social · 27/09/2026
I was in N. Norfolk on Friday & early autumn produced the most exquisite day. Light was soft & colours glowed. Here was just some ordinary Pelia endiviifolia growing in a pond. A pond sited within heath, bordered by Molinia & yet with a chalky base. Just look at the jade beauty of this liverwort!
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Dr Astrid Biddle @astridbiddle.bsky.social · 22/09/2026
Which ploidy is present will therefore determine the species mobility. It might be predicted that seeds allow distribution to ponds and headwaters. Bulbils are produced on the rhizomes. Of course these are tendencies. Here is a diploid with bulbils in the inflorescence!
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Dr Astrid Biddle @astridbiddle.bsky.social · 21/09/2026
This is from www.researchgate.net/publication/...
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Dr Astrid Biddle @astridbiddle.bsky.social · 21/09/2026
The seed needs to be properly ripe (brown or approaching) as immature seeds tend to look like neglectum. They need to be falling off into your hand.
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Dr Astrid Biddle @astridbiddle.bsky.social · 20/09/2026
Cape-pondweed (Aponogeton distachyos) is a magnificent and strange flower. A South African species, but another species planted in ponds and sometimes naturalised.
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Dr Astrid Biddle @astridbiddle.bsky.social · 20/09/2026
I find it interesting to consider what Flowering-rush (Butomus umbellatus) material is grown & planted, and what the implications are. Diploid material is fertile & has narrower tepals. Triploids are infertile & has bigger flowers with broader tepals, and produce bulbils. That's what we have here.
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Dr Astrid Biddle @astridbiddle.bsky.social · 20/09/2026
This made my heart skip a beat this week: Frogbit (Hydrocharis morsus-ranae) and Tubular Water-dropwort (Oenanthe fistulosa) growing in profusion side by side. They may have been planted in a garden pond, but nonetheless, what a triumph! Planted #WildflowerHour
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Dr Astrid Biddle @astridbiddle.bsky.social · 18/09/2026
Out in the field today and revisiting the S. erectum complex. L: x oocarpum R: erectum s. str. (I think these look like cupcakes)🧁
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Dr Astrid Biddle @astridbiddle.bsky.social · 13/09/2026
A lovely example of cryptic diversity: quillwort species can look deceptively alike, with their differences hidden in microscopic characters. Proximal view at ×40; megaspore 550 µm. With no velum or phyllopodia, this is the amphibious Isoetes phrygia, neither terrestrial nor fully aquatic.
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Dr Astrid Biddle @astridbiddle.bsky.social · 13/09/2026
My #favouriteplant of 2026 has to be Isoetes phrygia, seen submerged in a temporary pool on the Omalos Plateau, Crete. A rather wonderful example of cryptic diversity—and, as a spore-producing quillwort, perhaps cheekily stretching the definition of #wildflowerhour!
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Dr Astrid Biddle @astridbiddle.bsky.social · 11/09/2026
It's a really good time of year to look at Sparganium fruits as they become distinctive as they ripen and dry.
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Dr Astrid Biddle @astridbiddle.bsky.social · 11/09/2026
And S. erectum s.str. in Blackpool.
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Dr Astrid Biddle @astridbiddle.bsky.social · 11/09/2026
Here is Sparganium neglectum in Kent.
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Dr Astrid Biddle @astridbiddle.bsky.social · 11/09/2026
Branched Bur-reed brainteaser in Shropshire The broad, rounded fruits identify Sparganium erectum subsp. oocarpum, now treated as S. × oocarpum, a hybrid between S. erectum and S. neglectum. Partly sterile fruit heads provide a useful clue.
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Dr Astrid Biddle @astridbiddle.bsky.social · 05/09/2026
Winter annual Batrachium taking advantage of the drawdown. Its seeds need a period of drying before they germinate readily when the pond refills. Adapted to the pond's seasonal rhythm.
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Dr Astrid Biddle @astridbiddle.bsky.social · 05/09/2026
Common Water-starwort (Callitriche stagnalis) rushing to reproduce before the pond refloods. Fruit super-abundant, even on remarkably tiny plants. It seems able to fruit at a much smaller stage than the other Callitriche I usually encounter.
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Dr Astrid Biddle @astridbiddle.bsky.social · 05/09/2026
Amazingly large patches of Taper-leaved Earthmoss (Pleuridium acuminatum) across the sandy drawdown zone of a heathland pond. I don’t think I’ve ever seen quite so much of it.
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Dr Astrid Biddle @astridbiddle.bsky.social · 05/09/2026
I’ve found Orange Foxtail in quite a few ponds this year. It’s a plant of bare mud exposed as ponds and other wetlands dry out, and I’m wondering whether the dry spring and unusually early drawdown have made it one of the winners of this drought year.
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Dr Astrid Biddle @astridbiddle.bsky.social · 05/09/2026
If you know, you know… Bend the inflorescence of Orange Foxtail (Alopecurus aequalis) over and check that there really are no awns. A really nice thing to find in the drawdown zone of a pond.
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
Many thanks to the many kind and generous people who helped me in my search. @nhm.org @cuherb.bsky.social @herbarium.bsky.social @rbgkew.bsky.social
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
The project also reinforced how valuable herbarium collections remain as scientific resources. Historical specimens collected more than a century ago can still reveal overlooked biodiversity and entirely new ecological questions when revisited with fresh approaches. @bsbibotany.bsky.social
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
In Eleocharis, which possesses holocentric chromosomes, the relationship between genome structure and ecological behaviour may be particularly interesting.
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
What interested me most was that the story did not stop at taxonomy. The work raises questions about genome size, ploidy level, stomatal traits and ecological differentiation in wetland plants.
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
What emerged was a striking ecological pattern. The lower-ploidy subsp. palustris appears strongly associated with coastal grazing marshes, tidal river systems and floodplain wetlands, and is far rarer in Britain than I had expected from the literature and recording data.
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
By revisiting herbarium specimens from major UK collections, it became possible to reassess nearly 200 years of material using stomatal measurements taken directly from dried specimens.
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Dr Astrid Biddle @astridbiddle.bsky.social · 30/08/2026
Pleased to announce my new paper: Herbarium specimens spanning nearly two centuries revealed striking ecological & geographical differences between two ploidy-defined subspecies of Eleocharis palustris in Britain. Ploidy & genome size could help explain them. doi.org/10.33928/bib...
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Dr Astrid Biddle @astridbiddle.bsky.social · 28/08/2026
Today a scrap of Riccia fluitans in Surrey, clinging to moist decaying Typha, right in the middle of the pond. A needle in a haystack.
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Dr Astrid Biddle @astridbiddle.bsky.social · 27/08/2026
They don’t say which ponds the plants came from. But looking at this drawdown today: yes. You can see it. Just remove urban stuff and add cattle... then BOOM!
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Dr Astrid Biddle @astridbiddle.bsky.social · 27/08/2026
At Wimbledon Common today doing surveys. I remembered seeing a remarkable number of old Starfruit Damasonium alisma herbarium sheets from Wimbledon Common in the Natural History Museum collections. I loved how the plants that were virtually all seed and few leaves. Date was 17/8/1869.
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Dr Astrid Biddle @astridbiddle.bsky.social · 27/08/2026
Better known from arable and disturbed ground, but here behaving as an ephemeral drawdown species, taking advantage of the brief period of exposed, damp mud.
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Dr Astrid Biddle @astridbiddle.bsky.social · 27/08/2026
I thought these ponds were meant to be boring today! A massive patch of enormous Glaucous Crystalwort Riccia glauca rosettes on the drawdown at Dagnam Park, NE London.
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Dr Astrid Biddle @astridbiddle.bsky.social · 24/08/2026
Peak District UK, walking downhill from surveying a pond.
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Dr Astrid Biddle @astridbiddle.bsky.social · 19/08/2026
P. obtusifolius has declined in Britain, so it was particularly nice to see it growing in such luxuriant abundance. @bsbibotany.bsky.social
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Dr Astrid Biddle @astridbiddle.bsky.social · 19/08/2026
After a succession of fairly uninspiring ponds, this was rather nice. Huge amounts of Blunt-leaved Pondweed Potamogeton obtusifolius, co-dominant with Elodea nuttallii and carpeting the bottom of one of the large ponds at Swanholme Lakes.
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Dr Astrid Biddle @astridbiddle.bsky.social · 16/08/2026
But when you look at the landscape that was present before the reservoir here, it was already outstanding.
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
Perhaps, in some populations, what we are seeing is an extinction debt. Also present on the wet sediment was Juncus foliosus, itself close to the upper end of its known Iberian altitudinal range, with Corrigiola litoralis higher on the shore. A fascinating bit of reservoir drawdown.
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
A persistent seed bank can conceal that change for some time: plants may continue to appear even while opportunities to put substantial quantities of seed back into the bank become increasingly infrequent.
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
That has interesting implications for declining populations in s-e England. Habitat loss is part of the story, but increasing drought may also be shortening these reproductive windows.
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
The reproductive output was far greater than I am used to seeing in British populations. It made me wonder if the important factor is not simply drawdown, but how long the exposed sediment remains damp. A longer wet phase gives plants more time to grow, flower and seed before the substrate dries.
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Dr Astrid Biddle @astridbiddle.bsky.social · 15/08/2026
The reservoir drawdown was largely bare, but where streams & seepages crossed, they maintained patches of wet sediment. Here Limosella formed blue-green bands, with thousands of seedlings & tiny plants flowering profusely.
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