I can attest to what Kai says; I got a strain of pontiderifolia he threw in that was quite small and had melted back when it arrived.
But from just the tiniest stump that was left I now have a decent looking plant with many nice leaves.
I've seen crypts grow from bits of rhizome the size of a grain of wheat.
http://images.aquaria.net/plants/Cry...ne/u/UND/nubs/