Blue Toadshade

Lactarius indigo

When disturbed, this mushroom lets off a puff of blue powder.

Russulales

Lactarius

Russulaceae

The cap of the fruit body, measuring between 5 and 15 cm (2.0 and 5.9 in) in diameter, is initially convex and later develops a central depression; in age it becomes even more deeply depressed, becoming somewhat funnel-shaped as the edge of the cap lifts upward. The margin of the cap is rolled inwards when young, but unrolls and elevates as it matures.

The stem is 2–6 cm (0.8–2.4 in) tall by 1–2.5 cm (0.4–1.0 in) thick, and the same diameter throughout or sometimes narrowed at base.

its taste is mild to slightly acrid.

The cap surface is indigo blue when fresh, but fades to a paler grayish- or silvery-blue, sometimes with greenish splotches. It is often zonate: marked with concentric lines that form alternating pale and darker zones, and the cap may have dark blue spots, especially towards the edge.

Their gills color is an indigo blue, becoming paler with age or staining green with damage.

Stem color is indigo blue to silvery- or grayish blue.

Pungent, earthy.

The powder is commonly
used to color various inks and dyes.