 Lactarius indigo , commonly known as the indigo milk cap , the indigo ( or blue ) lactarius , or the blue milk mushroom , is a species of agaric fungus in the family Russulaceae . A widely distributed species , it grows naturally in eastern North America , East Asia , and Central America ; it has also been reported in southern France . L. indigo grows on the ground in both deciduous and coniferous forests , where it forms mycorrhizal associations with a broad range of trees . The fruit body color ranges from dark blue in fresh specimens to pale blue @-@ gray in older ones . The milk , or latex , that oozes when the mushroom tissue is cut or broken — a feature common to all members of the Lactarius genus — is also indigo blue , but slowly turns green upon exposure to air . The cap has a diameter of 5 to 15 cm ( 2 to 6 in ) , and the stem is 2 to 8 cm ( 0 @.@ 8 to 3 in ) tall and 1 to 2 @.@ 5 cm ( 0 @.@ 4 to 1 @.@ 0 in ) thick . It is an edible mushroom , and is sold in rural markets in China , Guatemala , and Mexico . 
 Lactarius indigo , commonly known as the indigo milk cap , the indigo ( or blue ) lactarius , or the blue milk mushroom , <a href='drop_aux' title='1'><mark>is</mark></a>a species of agaric fungus in the family Russulaceae . A widely distributed species , it <a href='uninflect' title='2'><mark>grows</mark></a> naturally in eastern North America , East Asia , and Central America ; it <a href='been_done' title='3'><mark>has</mark></a> also been reported in southern France . L. indigo <a href='uninflect' title='4'><mark>grows</mark></a> on the ground in both deciduous and coniferous forests , where it <a href='uninflect' title='5'><mark>forms</mark></a> mycorrhizal associations with a broad range of trees . The fruit body color <a href='uninflect' title='6'><mark>ranges</mark></a> from dark blue in fresh specimens to pale blue @-@ gray in older ones . The milk , or latex , <a href='null_relcl' title='7'><mark>that</mark></a><a href='uninflect' title='8'><mark>oozes</mark></a> when the mushroom tissue is cut or broken — a feature common to all members of the Lactarius genus — <a href='drop_aux' title='9'><mark>is</mark></a>also indigo blue , but slowly <a href='uninflect' title='10'><mark>turns</mark></a> green upon exposure to air . The cap <a href='got' title='11'><mark>has</mark></a> a diameter of 5 to 15 cm ( 2 to 6 in ) , and the stem <a href='drop_aux' title='12'><mark>is</mark></a>2 to 8 cm ( 0 @.@ 8 to 3 in ) tall and 1 to 2 @.@ 5 cm ( 0 @.@ 4 to 1 @.@ 0 in ) thick . It <a href='drop_aux' title='13'><mark>is</mark></a>an edible mushroom , and is sold in rural markets in China , Guatemala , and Mexico . 
Lactarius indigo , commonly known as da indigo milk cap , the indigo ( or blue ) lactarius , or tdablue milk mushroom , a species of agaric fungus in the family Russulaceae . A widely distributed species , it grow naturally in eastern North America , East Asia , and Central America ; it done also been reported in southern France . L. indigo grow on thdaround in both deciduous and coniferous forests , where it form mycorrhizal associations with a broad range of trees . The fruit body color range from dark blue in fresh specimens to pale blue @-@ gray in older ones . The milk , or latex , ooze when the mushroom tissue is cut or broken — a feature common to alll members of thedactarius genus — also indigo blue , but slowly turn green upon exposure to air . The cap got a diameter of 5 to 15 cm ( 2 to 6 in ) , and the dam 2 to 8 cm ( 0 @.@ 8 to 3 in ) tall and 1 to 2 @.@ 5 cm ( 0 @.@ 4 to 1 @.@ 0 in ) thick . It an edible mushroom , and is sold in rural markets in China , Guatemala , and Mexico .