There are a number of natural plant tinders that may be ignited using Wilderness Solutions fire pistons.
True Tinder fungus, Inonotus Obliquus, AKA Chaga. This is parasitic growth common to birches that may develop at the site of an injury to the tree such as a broken limb. This fungus has a blackened, charred looking exterior with an interior the color of buckskin and consistency of cork. The interior of this fungus makes remarkable tinder that is difficult to extinguish once ignited. The ease with which tinder fungus ignites varies with its texture. Learn to search out the best fungus for your fire piston by testing it with a thumbnail. Soft, spongy feeling tinder fungus ignites most easily and also works very well with traditional flint and steel. Harder, woody tinder fungus is best reserved for use with fire by friction methods. It requires no special treatment other that drying.
The pith of the mullein weed stalk may require two or three attempts before lighting. Once the ember has formed however it propagates well and can be used to light a fire much the same way as tinder fungus. Collect the stalks in late summer after they turn brown.
Milkweed Pod Ovum
The slender spike remaining in the dried milkweed pod after the down has dispersed ignites easily, however the ember has a short burn time. Pick it out quickly and use this to ignite a better coal extender. It can also be used with traditional flint and steel.
Roll the down into a tight ball and pack this firmly into the tinder cavity. In order to propagate an ember the fibers need to be in contact with each other. The coal does not last very long so again you will want to use the coal to ignite another longer burning coal extender.
Cattail fluff can be challenging to ignite. Follow the same procedure described above for milkweed down. The fluff may require multiple attempts and will begin to char before catching an ember. Pick it out quickly so it can breathe.
Basically, dry spongy rotten wood. Different varieties perform with different degrees of effectiveness. Sugar Maple punk performs best. Punk carries an ember extremely well and can be a very useful coal extender. It can also be used alone to light a fire. Just place two or three pieces together with a few wood shavings on top. If there is a little breeze this set up can be self-igniting with no need to blow on it. It can also be used with traditional flint and steel.
Poplar / Cottonwood cotton
Poplar cotton works the same as milkweed down. It has a very short 2 - 3 week period of availability in late spring.