Well, I just tried to make a texture for the lepidodendrons. I started off with a picture (which turns out to be gigantic) that I took of its bark:
http://img70.imageshack.us/img70/7479/goodpicoflepbarkbw6.jpg
After much hassle, I finally produced this not-quite seamless texture before giving up (...for now).
And the result (this is the good side of the tree--you don't want to see the other side, trust me. ):
Not bad for my first shot at texturing, eh? Don't answer that...
I think the bark is one of neatest things about lepidodendrons. Back in the day, lepidodendron bark was thought to be the squamous skin of giant fossilized snakes and was therefore called "snake stone." (Can you imagine snakes a meter thick? That would be seriously scary!) And can you guess what feature prompted someone to name the tree "lepido" (scale) + "dendron" (tree), the "Scale tree"?
The way the scales are produced is related to the way the the tree bears its leaves, which is veeery different and much more interesting (in MY opinion) than how trees bear their leaves nowadays. See, when a lepidodendron is young, it resembles your basic telephone pole. And straight out of the trunk, at the top area of the pole, grew a bunch of grass-like leaves, somewhat like the tufted tail of a lion or elephant, or a bottle-scrubbing brush. Except the leaves probably didn't stick out that much--they reached 8 inches long, tops. So as the tree grew taller, I *believe* the older, lower leaves were shed, and where they once grew the little diamond-shaped leaf scars which can be seen in the texture were left on the trunk. Of course, new leaves were produced at the top as the tree grew up.
It wasn't until the tree reached maturity that it branched and produced the nice bichotomous crown that all of my lepidodendron trees have at the moment (no babies in my simulation yet). Remember what "bichotomous" means? It just describes how branches split apart into smaller branches; for bichotomous branching, a branch splits in two and then those two smaller branches each split in two, etc. etc. Too bad we don't have many bichotomously branched trees these days; I think they would be neat to have around. Of course, so would the dinosaurs. Sigh... But if you look in Er'cana (or your Relto, if you have the page) you can see some trichotomously branched plants. They'll have to do I guess.