Common Glowcap

The Common Glowcap is a luminescent mushroom and is used as scenery in The Forest Navel in Pikmin 1, as well as multiple caves in Pikmin 2. A radioactive isotope known to Hocotatians as "Hocotatium 111" is what gives this fungus its pale blue glow, according to Olimar's Notes. As scenery, the Glowcap does not change gameplay at all.

Olimar's Notes
The light emitted from this rare mushroom is neither a reflection, nor a release of stored light. It grows not only on decomposing trees, but also on soil and rocks. This mushroom's fungal filaments are capable of stabilizing and concentrating pure Hocotatium 111. It is none other than the Hocotatium 111 approaching the point of critical mass that causes the glowcap's blue luminescence.

Louie's Notes
Rapturous fresh or sauteed, this illuminating fungus will be hot in the galaxy's trendiest restauraunts.

Pikmin:Redemption
There are many different color hues indicating how close the Hocotatium 111 is close to critical mass. Some colors include yellows, greens, blues, reds, oranges, and violets.