It has a single thin, hollow, onion-like leaf and up to one hundred small, pale green flowers.

[2][3][4] The south coast mignonette orchid was first formally described in 1990 by Robert Bates from a specimen collected in a swamp near Nornalup.

[1] The specific epithet (quadrata) is a Latin word meaning "four-cornered",[6] referring to the shape of the labellum.

[2] Microtis quadrata grows in seasonally wet depressions and in swampy mounds in near-coastal areas between Perth and Augusta.

[2][3][4][7] Microtis quadrata is classified as "Priority Four" by the Government of Western Australia Department of Parks and Wildlife,[7] meaning that is rare or near threatened.