Lentinus arcularius, also known as the spring polypore, is a species of fungus in the family Polyporaceae.

[1][2] It has been found on all continents, but has primarily been documented in the United States, Austria, Mexico, Australia, and Japan.

[3] It was first documented in 1783 by German naturalist August Batsch under the name Boletus arcularius.

It was later renamed to Polyporus arcularius in 1821 by Swedish mycologist Elias Magnus Fries before being recently (2010) transferred to the genus Lentinus.

The outer area of the cap (margin) has fine hairs.