I believe there was a comment earlier by someone who used a paper bag, I can't remember.So the sacks opened up,just like you said. Now I need to be careful and collect the pollen. I read somewhere you could just put the branches in a clear plastic bag and shake it. Would that both viabke and unviable pollen ? Can anyone tell if this is a photo or a auto ?
I just used a large ziplock bag and bent the stem into it and tapped the branch fairly stern, lightly shake it if needed. Or hold it wide open under the sacs and tap.
You have a lot dropped on the leaves too, you can shake those into the bag as well.
I used to do it for a couple of days to catch all the rest that open a little later.
I do not know if that is a photo or auto. Can't help there.
Edit: others may have different methods that work well for them too.
Edit: you may get some of the bits from the sacs in the bag, that's normal.