One more thing I found... good advice:

Fargesia nitida seeds

Weekend Gardener wrote:
I have never had the privilege of collecting bamboo seeds, but just in
case I do, I had looked it up a year ago. You can harvest the seed
individually by hand. But it seems the best way to know that it is ripe
is to allow it to fall to the ground, as they only fall when they are
ripe. In order to not leave things to chance, it is recommended that a
piece of cloth or a tarpaulin be placed on the ground, and the seed
bearing culm be shaken. The best germination rate is when the seeds are
sown fresh.