You can use finely cedar bark, jute twine, cotton balls, dryer lint, really dry grass, dead dry spanish moss, milkweed puffs, thistle down, and anything else that comes to mind. In my opinion jute twine nest is pretty hard to beat. You can also use a sombination of tinders for a nest. Cedar bark and jute twine do a great job together.
Whatever you have that is dry. If it to big just smash it with a rock to get if fluffy. This works with all kinds of wood and tinder. Get a big rock and no need for all that battoning.
I live over in LA, and find spanish moss is pretty worthless, as it's seldom 'dead and dry', and is suprisingly moist. Old man's beard is apparently a northern varient i've not seen or tried. we had birchbark when i lived in NY as a kid.
Best man-made tinder i've used with flint and steel is jute twine or cotton ball with petroleum jelly.
Haven't found a natural tinder yet that will work. Working on cypress, as it's pretty close to cedar, but apparently it has to be 'just right' to shred finely enough (dead, but not so punky it crumbles to dust, yet dry enough that it shreds). I think our humidity really causes some challenges.
Wish i had more cattail in more areas, or milkweed of any sort.
its wonderfull tinder, and can often be found dry even during times of rain as it is some what protected by the palm fronds... like and umbrella. i use the fibers from cabbage palms as i find this to be the easiest to light. the punkier the fibers the better.
this will only work for the OP if he is by the coast. hes in S. GA. , but cabbage palm only grows along the coast in GA.
it has been mentioned that all types of natural materials found in the woods can be used. the only way to find out what works for you is to try it out. fluff it, tear it, shred it, shave it, and try it out.
it was raining this day, but palm tinder works like a champ.
I used dogbane cordage. Lots of others in that contest used jute twine. Both are natural and both get a flame real quick, because both have the same properties. The palm tree tinder looks like it has the same properties as well.
Nice thing is, a small wad of either can be used over and over again and kept in your firesteel kit/ flint and steel tinder box. I've used a lot of natural tinders and these two, or anything else that has the same properties, work best for getting a quick flame.
But, as far as "what is best?" goes, sometimes a quick flame is not what I need. It all depends on the weather and what I intend to do with the tinder.