An LNHS meeting in Colindale, London Borough of Barnet, led by BMNH botanist Mark Spencer.
Mark is leading on the new Flora of London project (the last ran from 1966 to 1976), and the purpose of the visit was to get more records from a poorly-studied area that is within his own recording patch.
There was quite a big turnout, and by doing my usual thing of hanging off the back and side of the main group I found quite a few of the more interesting things that might otherwise have been missed including Stone Parsley (Sison amomum), Slender Trefoil (Trifolium micranthum) and Common Stork's-bill. Also Water Soldier (though this latter will have been put in the pond in Rushgrove Park deliberately). There was what I felt to be a disproportionate amount of interest the Swine Cress (Coronopus squamatus) I discovered hidden under some overhanging branches here - but apparently it's infrequent in north London.
Mark himself was excited by the Common Calamint (Clinopodium ascendens) I spotted in a front lawn on Colindeep Rd., because he says it's very uncommon in this part of London that was Middlesex, and various members started taking photos of it (luckily the residents didn't come out to ask what on earth was going on ....).
Later I went up to Edgware and Burnt Oak on my own and found a young Milk Thistle outside Burnt Oak Library in what appeared to be recently (re-)sown grass and a Wall Rue fern (Asplenium ruta-muraria) in the Watling Rd. railway bridge brickwork (pictures below).
There was a Little Egret in the Silk Stream near the Colindeep Road bridge, and a Long-winged Conehead cricket in Rushgrove Park.