In D&D 5th edition the dancing lights cantrip has "wychwood" as one option for its spell component. However googling for wychwood brings up a brewery, an art space, and wychwood forest in Oxfordshire none of which seem like a spell component. Does anyone know what "wychwood" the Player's Handbook is referring to?
Ulmus Glabra aka Ulmus Glabra Montana is also known as Scotch Elm, Wychwood, Wych Elm, and Witch Hazel. (Witch Hazel is a different shrub in the US). It was used to make divining rods and had other reputed magical properties.
One of the things you lose by just treating components as "junk" and abstracting them away is that it's one of the remaining sources of actually learning something about the real world from D&D, it was one of our favorite things with all the weird stuff in the DMG in First Edition. Don't reject the hold-overs, use them to learn about something other than rolling dice!
It could be witch hazel. Not an exact match, but the closest I'm aware of.
The more fundamental answer here, though, is that it really doesn't matter. Spell components are handled either as a single pouch that contains an infinite supply of every (non-costly) spell component under the sun, or a spellcasting focus that removes the need for them.
There are only 2 reasons I can think of why this question might come up in play:
- A spellcaster loses their component pouch/spellcasting focus somehow and is trying to find the spell component in the environment so they can cast anyway.
- You are trying to add interesting flavour to your game.
If the reason is either of these, the answer here is to remember that it's your world, and it's not the real world. Wychwood can be whatever you want it to be, and it can do whatever you want it to do.
For example, you might decide that wychwood is a type of tree whose twigs glow briefly when snapped, a result of its origin in the Feywild. Or you could say that it's a perfectly ordinary bush that has a dark and twisted appearance, so it was named wychwood and there are some odd superstitions about it. (Neither of these are very original, but this isn't my strong suit.)
The point I'm trying to make is that even if wychwood did exist in the real world, what it is in your world is up to you. It's a cool name, make up something cool to match it!