They range in size from the little laughing leek orchid (P. gracile) at about 15 cm (6 in) to the king leek orchid (P. regium) which grows up to 2 m (80 in) tall.Orchids in the genus Prasophyllum are terrestrial, perennial, deciduous, sympodial herbs usually with a few inconspicuous, fine roots and a pair of more or less spherical tubers partly covered by a fibrous sheath.

Leek orchids rarely reproduce by forming "daughter" tubers, relying on their flowers for reproduction.

A single onion or leek-like leaf develops near the base of the plant and accounts for the common name of the group.

The labellum has a callus which consists of a raised, fleshy plate which is usually channelled, with the base forming an inverted basin shape.

The sexual parts of the flower are fused to the column which is short and has narrow wings, often with a small lobe at the front.

[3][4][5][6][7] The genus Prasophyllum was first formally described by Robert Brown in 1810 and the description was published in Prodromus Florae Novae Hollandiae.

[5][12] In Western Australia alone, they grow in a range of habitats from the margins of salt lakes, to swamps and dense Karri (Eucalyptus diversicolor) forests.