The dried cattail seed head makes a great fire starter. It catches a spark very easily and burns quick. The fluffy seeds are also good for insulation when it is cold out. To use the dried fluff you need to build your fire pit with your smaller kindling and fine debris. Collect dried grass to build a birds nest shaped container and place the dried cattail fluff inside.
If you have a flint and steel set or ferrous rod, the cattail will take a spark very quickly. If you are using the bow and drill method, the hot coal ember will catch the dried fluff very quickly.
If you run across the cattail during your survival trek, make sure to collect a few seed heads to take with you. Be sure to keep the fluff as dry as possible.
And also remember that the other parts of the cattail is a food source.
Stay Prepared! Stay Alive!