Diuris systena is a
tuberous,
perennial herb with two or three grass-like, linear leaves long and wide. Up to four lemon yellow flowers long are borne on a green flowering stem high. The dorsal
sepal is egg-shaped, long, wide with a greenish-brown base and few faint stripes. The
lateral sepals are brownish-green, sword-shaped and parallel to each other, long and wide. The
petal blades are narrowly egg-shaped to narrowly elliptic, long and wide on a stalk long. The
labellum is long with three lobes - the centre lobe egg-shaped, long and wide, the side lobes erect, linear to narrowly oblong, long and wide. The labellum
callus consists of a central ridge with two hairy side ridges. Flowering occurs from late September to early November. ==Taxonomy and naming==