material consisting of seed coverings and small pieces of stem or leaves that have been separated from the seeds
I have no idea what a seed coverings look like, and what leaves separated from the seeds (what seeds) look like. Can someone post pictures of what a stubble can look like. It seems it can look like several different things. Google images gives a lot of pictures, but they don't really tell me what a stubble is. Looking at the pictures, I feel like it's the stem of harvested plants, but it doesn't really fit the definition, because it doesn't cover "seed coverings" part.