Why is the acornshell endangered?
I'm not sure what species your referring to. The International
Union of Conservation for Nature, or the IUCN Red List, doesn't
have a listing for the Acorn-shelled Barnacle. Considered that this
might be a different species, or even a plant / tree, I widen the
search and still didn't come up with anything that was close to the
name that is listed in this question. As far as I can tell from the
IUCN Red List, the Acorn-shelled Barnacle, and the Oak tree, aren't
listed. There are over 1,000 species of barnacles, the scientific
name, would help to narrow the search for this specific one in
question. For more details, see the sites listed below.