I'm currently writing a story in the universe of the role playing game "Mahamot".
Basically, in this world, what's left of human kind lives on huge spaceships swarming with little plants called "micelis" (it seems to be a French game, so I don't have any translation for this word which doesn't even exist in French). The description of those micelis is unclear but they are mostly a mix of mosses and lichens and their size ranges from one micron to ten centimetres. There are several thousands species of micelis and they are the base materials for everything humans need (clothes, food, weapons...).
Now here is the rub : in this game, swords, axes, knives and so on are said to be made of a something that closely resembles metal. So how can people turn mosses and lichens into such weapons ?
Two problems :
- A plant doesn't seem to be hard enough to forge a weapon. So micelis have to be transformed in a way that reinforces their structure. That being said, micelis aren't precisely described so if you can imagine how can some species naturally came to become stiff and hard, that'd be great !
- Since micelis are ten centimetres long at best, you have to use several of them to forge a weapon. But how can you mix them together into one object that won't break each time you hit something ?
Feel free to invent micelis species and features that would allow them to be turned into weapons more easily. As long as those features are plausible for a plant and respect the few indications I gave about micelis, it's OK with me.
Remember that everything you use to turn micelis into weapons is also made of micelis. In particular, I only have access to chemicals that can be created by plants.
Last thing you should know : there is absolutely NO magic in this world.