![Lophophora williamsii [CC-BY-SA-4.0 Steve Cook]](https://www.polypompholyx.com/wp-content/uploads/2019/01/Lophophora_williamsii_Barbican-e1546431378449-225x300.jpg)
The Barbican is a sprawling concrete brutality as apt to divide opinion as Marmite or skinny jeans. Built in the 60s and 70s as a housing estate and cultural centre on a vast bomb-site in the City of London, it does not sound like a promising place to go botanising, but after the fire-weed was …