I know only that different strains/varieties do indeed have differences in the serrations of leaf edges. For instance, the classic Cali O double-serrated leaf margin.
However, either last night or night before last I was watching some show, I think it was on a dinosaur bone pit in Alaska, on the north slope IIRC, and they had tons and tons of fossil plants. So they go through all these experts who explain how they determined
climate to within just a couple of degrees Celsius based on, get
this, LEAF SERRATION.
Plants that come from tropical, wet climates tend to have predominantly smooth leaf edges. This seems to allow water to shear off and I *think* may have something to do with transpiration. Plants from more temperate climates have predominantly serrated leaf edges, and this has something again to do with transpiration, but I think it's also affected by how cold the winters get in the particular environment. Now I wish I could remember the name of the program and what episode, I'm pretty sure it was on PBS.
AHA! Damn... that sure took some searching:
http://www.pbs.org/wgbh/nova/arcticdino/
In any event, I think it's a genetic trait carried over, but have no idea how dominant it might be or what might trigger expression.
I ramble. But I see a light at the end of the tunnel and it's
not a train!
