What plant are these from?

[hilla]

I bought a box of 30 of these root/stick/vines a few years ago at a craft store for $5-7. They were being marketed as floral decoration.

Now I have a use for them and need to find a supply source. What plant are they from?

They're lightweight, woody, and seem to be hollow in sections. The rest of the innards are like a strong, hard foam (can't dent it with a fingernail). They look like they've been bleached or sandblasted. Many are more twisted than shown in the photo, and the root-like areas are gnarled in appearance.

This is my third forum attempting to identify them. So far, they're not manzanita or driftwood but holdfast seems to be a possibility.

Any thoughts are appreciated! Thanks.

[JackBean]

seems like mushroom eaten by worms