It strikes me that you have a beautiful graphic illustration of the spiral phyllotaxy of a rose, and how it relates to the rest of the stem's growth. (pentastichous phyllotaxy?) http://www.biologydiscussion.com/leaf/p ... taxy/13243
I suppose that pattern exists on the stem in other roses, but wouldn't be so self-evident. I wonder what caused the segregation of thorns and non-thorns. It will be interesting to see if the twigs developing from the nodes on the smooth face will bear thorns.
[size=small][color=#669966]Zone 8 / Sunset Zn 30 (Austin, TX -- formerly New Orleans, LA)[/color][/size]