Last fall while wandering the woods behind our building I found a path that went right down to the river's edge next to a stand of cattails.
I had always read that cattail roots were a great source of flour so I decided to root around in the muck. I took a garden weasel, a bucket, and some hand shears to see what I could find. After a short learning curve I was able to pick out a few choice roots.
Covered in muck I dragged them back to the picnic table and gave them a quick scrub.
The hard part was keeping the muck out of the broken ends and the smashed sections. I washed them better in the sink and then peeled the outer layer off of them, discarding the bits that had gotten muddy.
I found at this point the easiest way to separate the starch from the pulp was to immerse them in water and then just work all the fiber until the starch falls out, then decant and dry. I also tried drying the roots then mashing the flour off it, this was much more labor intensive though there was a color difference in the flour.
You can see the dried then separated on the left.
I had also tried boiling sections of the root, this didn't do anything to help the starch fall off but it did cook it into something resembling a potato with fibers in it. If I were lost in the woods this would probably be the best way to turn those cattail roots into something palatable. I might also try in the future to make chicha using this method, it will probably be way easier than chewing on all that dried cornmeal.