Pterostylis baptistii is a terrestrial,
perennial,
deciduous,
herb with an underground
tuber. Flowering plants have a rosette of between four and eight stalked, dark green leaves, each leaf 30–80 mm long and 20–25 mm wide. A single flower 40–60 mm long and 20–30 mm wide is borne on a spike 200–400 mm high. The flowers are white with green and brown markings. The
dorsal sepal and petals are fused, forming a hood or "galea" over the
column. The dorsal sepal curves forward with a sharp tip and is the same length as the petals. There is a wide gap between the petals and the lateral sepals which have swept-back, thread-like tips 25–35 mm long. The
sinus between the lateral sepals is almost flat with a central notch and bulges forward. The labellum is 18–22 mm long, 5–6 mm wide, reddish brown and protrudes above the sinus. Flowering mainly occurs from July to November. ==Taxonomy and naming==