As he lay there in the soft loam, feeling the cool trickling of the water passing over his stiff tendrils, the newly christened Pete felt a stirring within himself. The sunlight that now struck him was filtered by an atmosphere, and gentle in its action upon him. Pete prodded his memory, and suddenly decided that silicates, after all, are not the most comfortable of linings for one's tender green cells. He seemed to recall a state of lush, sybaritic softness, in pre-silicate times. Decidedly, the silicates must go, thought Pete.
And go they did, molecule by molecule, down into the earth through his roots, which were now acting as tiny spigots, getting rid of the scratchy stuff that had bolstered the cell walls against change for millennia past, leaving Pete softer, greener, livelier, and a constant delight to the heart of Peter W. Merrill the First, whenever he came out to tend his plant, between pages of his thesis.
Pete, after spewing the last hateful molecule away, reversed his tiny fibre engines, and began to draw in. He drew in all sorts of things, as the days passed. A lot of minerals, and just enough water to float them in. Mostly, Pete's growing hunger sought out iron. Pete didn't know why he wanted iron, any more than a smoker knows why he wants another cigarette, but Pete's interest in iron was as intense as any smoker's in tobacco.
Above the ground, he grew very few inches larger, merely broadening his dark, green spiral leaves a bit to catch the tiny amount of warmth he required for growth. But beneath the soil, as with any tuberous plant, his roots were spread in a rough circular spoke-like pattern that reached about ten miles in every direction.
Pete Senior, had he tried to dig his plant up, would have been very much surprised to find he could not do it. But he didn't try, so his life went on as usual, with no surprises, which is the way he preferred it, so he was happy enough.
It wasn't until his paper had been duly published, and botanical cronies had shaken the dust from their whiskers and toddled around to see this enviable possession, that something of the root structure was discovered.
"Seems to spread underground," one remarked.
"Kind of a lunatic crab-grass," another jibed.
"Sure you're not pulling our leg, Merrill?" said a third. "Seems a bit stunted."
"Gravity," said Pete Senior. "Not used to it yet."