My last post to this thread ... Nigel Parsons, re Welsh units wearing leeks instead of a cockade; I haven't heard of that as a custom. (Some) Welsh units do indeed attach leeks to their headgear, on St. David's Day (Dydd gwyl Dewi Sant), March 1st. Although not in a Welsh unit, I did don a leek which Max Boyce might have envied on one March 1st, and discovered that Senior NCOs' sense of humour is very much a one-way process...

I suspect that leeks issued for wearing would probably have been eaten immediately, especially on active service. I note that when vegetation was used as a distinguishing mark, it was usually inedible. I have heard of oak leaves being used as such; also thistles, even though these might present problems.

One interesting bit of trivia re. this debate on Grenadier Caps and Fusilier Caps occurred to me. One famous battle of the British Army was Minden, in Germany, in 1760. The six British infantry units present marched through a park or garden before taking position, and five of the six plucked roses and stuck them in their (tricorne) hats. Their descendants (sorry, don't know which units these are) may wear roses in their headgear every year on "Minden Day". The one regiment which did not join in this dressing-up was the 23rd, the Royal Welch Fusiliers. I can only assume that this is because they were all wearing Mitre caps or Fusilier Caps, which did not have anywhere convenient to attach a very thorny piece of flora.