Bean in 2000, though the taxon had been noted by Rica Erickson in her discussion of S. muscicola variation in 1958.

The specific epithet ensatum is from the Latin ensatus, meaning sword-like, which refers to the shape of the floral throat appendages of this species.

This species generally has one to three scapes and cymose inflorescences that are 8–16 cm long.

S. ensatum is endemic to the area around Darwin in the Northern Territory of Australia.

Its habitat has been reported as being a "Melaleuca viridiflora-Lophostemon lactifluus forest with damp peaty soil."