Murder Most Florid

Let's hear it for diatoms! They are microscopic, unicellular algae fantastically abundant in wet places across the world. Not a patch on Prochlorococcus abundant, mind, but that's a prokaryote. One interesting thing about diatoms is that they have silica, rather than calcium carbonate, shells. This material is rather more resistant to degradation; perhaps because everyone else is avid for calcium. The other diatom 'fact' is their remarkable diversity of form - as sampled above from the Nat Hist Museum in London.

With their diversity, you can imagine that diatoms might be useful in forensics but TIL that they are particularly useful in cases of drowning. The smaller members of the tribe can be forced across the alveolar membrane when water under pressure floods the lungs and finish up embedded in various tissues including the liver. One standard forensic technique is to "ash" a necropsy sample from such tissues and then wash out the impervious-to-fire silica skeletons to determine if the drowning occurred at sea or in a lake or in a bathtub. Each of those habitats hosting different varieties of diatoms.

This is not all I learned from reading Murder Most Florid: Inside the Mind of a Forensic Botanist (2019) by Dr Mark Spencer. I won't link to the publisher because, a) the book is basically out of print because Quadrille under-estimated the take-up b) the book has been published with two missing pages. Check your library, though, because it's worth a leaf through (see wot I did there?). Spencer's work is adjacent to that of Patricia Wiltshire, who works in the same arena as a forensic palynologist (pollen-boffin). They have both been free-lancing = scrabbling for work on zero hours non contracts from police-services across the UK. Between 1991 and 2012, there was a UK state-owned FSS Forensic Science Service. It was available as a service to the several police forces . . . but also coroners, the Revenue, prosecutors. Then it was shuttered because it was costing money and half the staff went free-lance. I'm sure that the created competition is great for Das Kapital.

Most crime (Forensics:the application of scientific methods and techniques to the investigation of crime) happens in houses, or on the mean streets. Forensics in this world is about glass fragments, gunshot residues, blood-spatter, exit wounds. Most coppers never get out in the countryside and are a bit at a loss when scene-of-crime hinges on bending of grass-stems, the length of bramble arches, leaf-frags in trouser-cuffs. They are more inclined to call up a boys-toys back-hoe, than a fastidious botanist in wellies. A back-hoe will dig up the body if it's there, Yes,  but with a lot of extra metal-on-bone marks to bamboozle the forensic pathologist like Richard Shepherd. Cripes, I've been reading too much about dead-body science.

Who knew that a really experienced botanist can name a plant species from a 1cm² fragment of leaf stuck to a muddy boot-heel? For most of us, beyond ash Fraxinus excelsior and daisies Bellis perennis, we'd be hard-put to dredge up common name, let alone a Linnaean binomer, for a whole in situ random plant from the neighbourhood - even if it was in flower. Quiz-time [L]: under what species of tree was the bludgeoned Together For Yes activist having a picnic? A: at page bottom.

It's true that police services have long ago given up on the ideal of solving all crime. They probably won't bother to call by if you phone-in a burglary: "Just call your insurance, Sir". They have a budget and a set of priorities and nailing a perp to a particular place through botanical trace-work is a) alien e) expensive, so it's not done. Drs Spencer, Shepherd and Wiltshire think that justice is a missing a trick there; but perhaps everything looks like a nail to a hammer and they would say that wouldn't they? If you read either of the forensic botanist memoirs, you'll be in a better position to judge whether "we" need that expertise. Nobody has made a convincing case that "we" need synonymous codon usage analysis, however much fun I had working in that field for a decade.

Mark Spencer addresses the Linnaean Society on his book and work.
A: Acer pseudoplatanus, sycamore Seicmar