Sparkin and Pyrobark
Sparkin form at at the end of a lightning storm, but are very vulnerable to being put out by stray raindrops. Pyrobark form when the trees around them finally dry, but remembering the damp of the outside world they protect themselves inside the trunks of deads trees, burning it slowly.
When taken under the wing of a trainer, or very rarely by their own account they can either overcome their worry and evolve into Hengnis if they evolve in the wild. They bridge the gap between trees, often initiating wildfires for amusements sake. Those that do quickly learn a valuable lesson that a tree can only be burnt once.
Alternatively, if they choose to live a slower more comfortable life, and evolve while in civilisation, they settle into a Pehwr, more peacable and more stable, and nestles into the dry earth around itself. This forme is preferred amongst the peoples of Ishi, though some warriors make good use of Hegnis.