These mushrooms get their name from the milky liquid they exude when cut or damaged. Color of liquid and color change after being exposed to air should be noted; as well as smell and taste. Trees in vicinity of collection area should be documented. All of these factors can help with identification. The genera Lactarius and Lactifluus are mycorrhizal, having symbiotic partnerships with trees and plants. Consistency is often brittle. Gills are attached, sometimes decurrent. Cap surface can be smooth, velvety or sticky; sometimes with a zonate pattern. Note any pitting on stem. White to yellow spore print.

Milk Cap Mushrooms at Indiana Fungi

Resources:

See Milky Caps: Lactarius and Lactifluus (with keys) at MushroomExpert.Com