Those are a couple of Huisache rootballs. Someone asked me how the hollow form I posted looked like before I turned it and I posted that pic.
The HF is posted here http://www.penturners.org/forum/topic.asp?TOPIC_ID=21699
The part I used is similar to the section above the ruler. If you noice, the one on the right where the bark was stripped (near the end of ruler)...it is very curly []