Glowstem

Games

 * Pikmin:Redemption
 * Pikmin: Wrath of Mr. B
 * Pikmin: The Rise of the Illuminati

Appearance
A two-stalked "plant" that is topped with a glowing colored cylinder. The possible colors vary by game:

 Pikmin:RedemptionThere are red, green, blue, and grey variations. 

Pikmin: The Rise of the Illuminati
Glowstems are a major part of this game (Notice how the scientific name has illuminati). The Illuminati uses these to power their war machines, and, later in the game, Olimar can collect these to power his own machines to fight back against the Illuminati.