 The convex cap measures 30 – 80 mm ( 1 @.@ 2 – 3 @.@ 1 in ) in diameter . Slightly sticky when wet , the cap surface is shiny and smooth . Sometimes , the surface has flattened filaments ( formed from aggregated hyphae ) , and may develop cracks . The thin and easily detached cap cuticle is initially reddish brown to dark brown , later becoming cinnamon brown . The cap margin is curved inward when young , but becomes bent downward when mature . The white to very pale yellow cap flesh does not change color when exposed to air , and has a pleasant odor and mild taste . The tubes comprising the hymenophore on the underside of the cap measure 3 – 8 mm ( 0 @.@ 1 – 0 @.@ 3 in ) long and are pale yellow initially before developing a greenish tinge in age . The pore surface does not stain when it is bruised . The pores are roughly spherical or polyhedral at first , becoming angular to pentagonal in age , and almost gill @-@ like near the attachment to the stem . Pores are about 1 – 2 mm in diameter . The stem is solid ( i.e. , not hollow ) 3 – 5 cm ( 1 @.@ 2 – 2 @.@ 0 in ) long , 10 – 15 mm ( 0 @.@ 4 – 0 @.@ 6 in ) thick in the upper part , expanding to 2 – 2 @.@ 5 cm ( 0 @.@ 8 – 1 @.@ 0 in ) at the bulbous base . It has pseudorrhiza ( cord @-@ like structures resembling a plant root ) that are 0 @.@ 5 – 1 @.@ 5 cm ( 0 @.@ 2 – 0 @.@ 6 in ) long . The stem surface is dry and smooth except for a powdery region near the apex . The top of the stem is yellow , but it gradually becomes reddish approaching the bulbous base . The stem tissue is pale yellow , although tunnels dug by insect larvae are reddish brown . 
