I could swear they were clovers, but now that you say that, it does look like there are little feelers like you'd see out the top of a pea plant. One theory that could make them peas is, I let my peas go and didn't even harvest any. They got woody and I just left them lay. Maybe a mouse or chipmunk grabbed those dried pods and buried those peas in a cavity under some wood buried in the hoog. That may also explain why I got all of that out without breaking the roots. I also don't think any clovers have thick roots like that.
Damn, I thought I had the biggest damn root nodules anyone on earth has ever grown.