Dr Astrid Biddle

A single-site occurrence indicates that it has long since ceased to function as a metapopulation. The local landscape processes & conditions "up & gone". It is then worth examining the species' likely operating range, & see where those conditions (management etc.) still work, or be made to work.

Temporal trends (1982–2021) in annual aboveground net primary productivity (ANPP) and community-weighted mean GS (CWM GS) and annual ANPP of large (≥ 5 pg/1C) and small (<5 pg/1C)-genome size (GS) species, and relative proportion (%) of annual ANPP assigned to large- and small-GS species (P < 0.05) at study Site-L and Site-S. Shaded areas indicate 95% confidence intervals.

Warming induced miniaturization of plant community genome size

Li et al.

nph.onlinelibrary.wiley.com/share/JECEMU...

It's a winter annual, so the rosettes slowly grow through the winter for a head-start the next year. Interestingly, many fewer plants appeared than rosettes promised.

Mr Poland came to Herts one Jan in search of a bird that all the twitchers were after at Woodoaks Farm. He submitted some records from that location, and I asked him that if he was getting bored waiting, he could help out and record the Torilis arvensis rosettes. He did! Through his binolculars 🤣

A new extreme of meiotic evolution:

✔️ 𝗻𝗼 crossovers
✔️ 𝗻𝗼 gene conversion
✔️ 𝗻𝗼𝗿𝗺𝗮𝗹 meiosis & fertility

Sex mimics clonality without becoming asexual, in the holocentric multicellular eukaryote 𝘙𝘩𝘺𝘯𝘤𝘩𝘰𝘴𝘱𝘰𝘳𝘢 𝘵𝘦𝘯𝘶𝘪𝘴.

more about it:
www.biorxiv.org/content/10.6...

Grass. Agrostis?

Common Gromwell (Lithospermum officinale) and a thin stick of wintery Wild Liquorice (Astragalus glycyphyllos) on the scrub edge. Identifiable by the woody growth.
Wild Liquorice recorded in 1988.
@bsbibotany.bsky.social @wildflowerhour.bsky.social

And a new species for me. Didymodon icmadophilus lying in sheets over the clinker. A very uncommonly recorded species. www.britishbryologicalsociety.org.uk/wp-content/u...

Abietinella abietina, a species widespread in the post-glacial period, served as an apposite reference point, making the comparison thought-provoking.
Oddly, it seems to be loosely attached to the substrate: strands lay unattached within the patches. It seemed as though this aided distribution.

Abietinella abietina
We descended to the railway track, where the clinker retained the characteristics of low-nutrient chalk grassland, with potential to support less competitive species. The skeletal soil over the substrate was easily scuffed, exposing bare ground.

Homalothecium lutescens is typical of dry calcareous turf. Shown here with Common Rock-rose (Helianthemum nummularium), which was disappearing under the scrub.
Scant amounts of Ctenidium molluscum.
In general, the bryophyte diversity was markedly reduced.

Yesterday I was with the Cambs Bryologists at the Devil's Dyke, an Anglo-Saxon causeway of chalk, sometimes reaching 10 m in height next to a deep ditch.
It supports chalk grassland CG3/CG5, with CG5 occupying a holding position between grassland & scrub.
Rhynchostegium megapolitanum- path edges

My Nitella dixonii record from Portugal looks good 😀🌿
Not extinct! Last record there in 1938.
Thanks
@nhm-london.bsky.social @bsbibotany.bsky.social

Thanks to Haley Gladitsch (algae herbarium)
Syntypes: all the original Nitella dixonii specimens everyone argued over in 1911.
Lectotype: the one specimen later picked to stop the arguing (“THIS one means the name”).
Isolectotypes: its siblings from the same collection- important, but not the boss.

This week I spent the day at the Natural History Museum trying to decipher a herbarium sheet of Nitella dixonii with more labels than plant🌿
Taxonomy is basically historical detective work with dried algae & decades of marginalia= notes, scribbles and polite disagreements written all over the sheet.

Penny Pond.

It's Stoke Common, and a photo for illustrative purposes.

An interesting paper.#

Not all dandelions are apomictic. Taraxacum platycarpum is sexually reproducing and self-incompatible, so population structure depends on genetics and pollination.

That's lovely- thanks for showing.
I wonder if there was an aquatic plants one too?

Wednesday 🙂🌿

I'm visiting the algae herbarium this week, so I shall have a look!

I had the sand dunes one too, but Hertfordshire was so far from the sea that I found that more difficult to relate to.
I would love to have copies of all the posters now.

Did anyone else have this poster on their bedroom wall growing up? "Chalk Grassland."
This was basically one of the gateway drugs into botany- not only the plants but importantly they communities they grew in.
I loved this poster & it still lives vividly in my imagination.
@bsbibotany.bsky.social

I found myself wondering whether this path might once have served as a drovers’ route, linking mudplant populations through the steady movement of livestock bound for London. Thinking this week about Starfruit.

Surprised to see so much Leucobryum sp. at Farnham Common (leaf sections next time). Joined by Diplophyllum albicans- I rarely see this in Herts, so very nice! But so common nationally. An unplanned journey, but very welcomed & neatly concluded with a warming Indian breakfast at a café near Burnham.

Dendrotelma - knotholes (!) in boundary coppiced Beech. Considering the closeness of the population of Codonoblepharon forsteri (Knothole Moss) I wondered if it might lurk at the edge of Farnham Common. Any space was covered by the more competitive Brachythecium.

Large areas of standing water now sealed beneath clear ice.

The ice was translucent, a window into a submerged world. From beneath it bubbles rose from submerged Lesser Spearwort (Ranunculus flammula), its rosettes with leaves widely spread beneath the ice.
@bsbibotany.bsky.social

Winter walk from Stoke Common to Burnham Beeches ❄️

Surface water was extensive at Stoke Common & continued in a similar form as we progressed. By Farnham Common, water was no longer held and beneath the Beeches was dry & stony. I follow a route I later discovered forms part of "Shakespeare’s Way".

A slightly lower pH? Bladder Sedge is interesting as that came up strongly at the resurrected ghost pond at Colney Heath.