Nectar weed

Because this subject has no official name, the name "Nectar weed" is conjectural.

Some White Pikmin plucking a patch of Nectar Weed.

Nectar Weed is found in a number of overground areas in both Pikmin games, and resembles a patch of long grass. Its purpose for Pikmin is as a source of Nectar: they can extract pools of Nectar from it seemingly by plucking out single leaves of grass. There is no need to swarm the Pikmin to the patch, as they will attempt to use it whenever they walk over it. Only five Pikmin can be pulling a patch of nectar weed at a time.

As with Rubble, Nectar Weed can be found in every area of Pikmin 1, but only in the Awakening Wood and Perplexing Pool in Pikmin 2, and never underground.