Pterostylis graminea is a terrestrial,
perennial,
deciduous,
herb with an underground
tuber. It has between four and six erect, linear to lance-shaped, grass-like leaves which are V-shaped in cross-section, long and wide. The top-most leaves are the longest and are higher than the flower. There is a single yellowish green flower with transparent white stripes borne on a flowering stem up to high. The
dorsal sepal and
petals are fused, forming a hood or "galea" over the
column. The dorsal sepal is more or less erect near its base then suddenly curves forward then below horizontal. The petals are slightly flared and slightly shorter than the dorsal sepal. There is a wide gap between the
lateral sepals and the galea and the lateral sepals have thread-like tips which are erect, spread slightly apart from each other and are higher than the galea. The labellum is greenish-brown, darker near the tip, curved and protrudes above the sinus. Flowering occurs between September and January. ==Taxonomy and naming==