It was outside a plant shop. The guy (worked at the centre) loading bags of dirt into my boot was there as I stood on it, it was maybe 4 inches long and only a cm wide and I asked him what it was and he shrugged and I let him know I was taking it and he looked at me like I was crazy but I could see it had some fine roots. Anyway, it survived although it looks a little strange. Thanks for your advice, I'll do that.
