Having deduced that his sensory epithelium was metallizing in tandem with his heart and cardiac muscle, Shen Cong felt good about it. Anything that let him finish the metallic gradation of every last tissue faster was, naturally, a wonderful thing.

In that good mood, he went back to sleep.

The next day dawned clear and fine.

Shen Cong set his research aside for half a day and drove out. He meant to pay a visit to the dragon-claw pagoda tree. This Beyond-Four-Star tree—who knew what its deal was—had genuinely put down roots right beside the Beijing–Shanghai Expressway. The little yellow flowers up in its crown had withered, replaced now by small, blue-green fruit.

Whether they were gold-fruit or iron-fruit, he had no idea. He had no intention of getting close enough to find out.

His truck was carrying a load of broken pagoda-tree branches, all of them knocked loose during the mushroom war, when the Bug Warriors had blasted them off with Mushroom Cannons and Mushroom Arrows. He'd studied these branches a few times over, but between the shortage of free hours he'd only ever given them a rough once-over, and had turned up nothing of value.

He parked within the reach of the tree's canopy, stayed in the truck, and switched on his Third Eye Radar to study the changes in the dragon-claw pagoda tree, careful and thorough.

This fully metallized pagoda tree was hard to slot into any evolutionary stage.

Still, Shen Cong roughed out a simple classification for it.

He pulled together everything he'd observed of how the evolved trees in the area went through metallic gradation, and found that the bark was always the first part to metal-change—it had begun back at the very dawn of the apocalypse.

After the bark came the outer growth rings of the trunk and the venation of the leaves; then the leaf blades and the roots; then the flowers, the fruit, and the innermost core of the growth rings.

Broadly speaking, that made five progressive tissue stages: bark, venation, roots-and-leaves, flowers-and-fruit, and heartwood.

The dragon-claw pagoda tree had already metallized…