Shoots are immature trees, at this stage of growth the species can't be identified. You can find these in Perplexing Pool and in cave sublevels. Rivaled by Foxtail, these could be the tallest named plant in the game. Shoots can be found in the backround in the stage Distant Planet in Super Smash Bros. Brawl for Wii.
"This is a young shoot of some kind, but what kind of tree species does it belong to? What shape will it take when it matures and grows to full height? Unfortunately, we are only able to obtain information from our portable scanners on a select few of the countless number of species we've encountered. But even if our expedition yields only brief observations on the life we encounter, it will still provide a better understanding of this bizarre planet."
"Inedible. And yet strangely delicious.