I’m thinking these firm, brown 4 inch-wide items from a Sarasota neighborhood are NOT actually nuts. Maybe not even fruits.
It looks to me like there are root and shoot buds showing on the surface, and maybe this tropical tree presumed vegetative growth would float, find its way to land elsewhere, sprout roots and shoots, and thus become established in new territory.
That story could be all wrong.
Surely somebody will recognize these lumpy unknowns. Anyone?
I suspect that they are the fruits of dioscorea bulbifera, air potato. At this time of the year, the vine is dormant and these fruits lie all over the ground. Beware the Ides of March – that is when the big tubers start to sprout. The tubers can be as big as basketballs. I fought this plant for three years and used 15 gallons of RoundUp concentrate to eradicate it. It is a very bad exotic vine.