Indigo Milk Cap

Conservation Status

IUCN Red List

not listed

NatureServe

not listed

Minnesota

not listed

Description

Indigo Milk Cap is a widespread but uncommon, distinctively colored mushroom. In the summer and fall it can be found on the ground alone, scattered, or in groups, in oak and pine woodlands. It grows on the roots of hardwoods, including oak, ironwood, and blue beech; and pines.

When young the cap is convex or depressed at the center and the margin is rolled inward. It is deep blue or medium blue and often has concentric rings of color. It is smooth, dry, and 2″ to 6″ in diameter. It is sticky or slimy when wet and exudes a bright dark blue latex or “milk” when cut. The latex eventually turns dark green when exposed to air. As the cap ages it becomes flat or vase-shaped, the color fades to silvery-blue, and it may develop greenish stains.

The flesh is whitish-blue. It stains blue when it is cut, then slowly turns green. It is edible and tastes mild to slightly bitter.

The gills are bright dark blue when young, becoming pale as they age, then yellowish at maturity. They are closely spaced and widely attached to the stalk, slightly running down the stalk on mature mushrooms.

The stalk is bright dark blue, silvery-blue, or grayish-blue, rigid, ¾″ to 3⅛″ long, and ¾″ to 1″ in diameter. It is slimy when young but soon becomes dry. It often develops irregular pits. It becomes hollow when it ages.

The spore print is creamy yellowish.

Similar Species

Indigo Milk Cap is the only milk cap mushroom that “bleeds blue.”

Habitat and Hosts

Deciduous, mixed, and coniferous forests. On the ground. Hardwoods, including oak, ironwood, and blue beech; and pines.

Ecology

Season

July to October

Distribution

Sources

7, 24, 30, 77, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 9/22/2026).

Lactarius indigo (Schwein.) Fr. in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-08-26 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgyy9

Mycology Collections Portal (MyCoPortal) https://www.mycoportal.org/portal/collections/index.php). Accessed 9/22/2026.