(3334) fungi under Birch
Found growing near oaks and hackberry. Milk white, drying white. No noticeable odor.
Found in a pine-oak forest. When cut, gills exuded a white latex which stained red.
This seems to fit the description in Metzler.
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid ('latex') if cut or damaged. Like the genus Russula, with which they are grouped in the family Russulaceae, their flesh has a distinctive brittle consistency.