[1] Pluteus microspermus was originally described by E. Horak in 1981 but first published in Volume 5 of The Fungi of New Zealand (2008).

[1] The holotype specimen was collected by E. Horak in 1981 from rotten wood or bark in the Waitākere Ranges near Piha, in New Zealand.

[1] The pileus can be light or dark brown with a sooty appearance and is large, between 40 and 100 mm in diameter.

[1] The gills (lamellae) are not attached to the stipe and change colour, from a pale white through to pink and finally dark brown on the edges.

[1] The stipe is white to light grey but covered with rough brown fibrous material (fibrils) that look scaley.

[1] Pluteus microspermus can be found growing on native broadleaf trees' rotten wood and bark, including Leptospermum, Kunzea, Fuscospora fusca and Lophozonia menziesii.