Pterostylis angusta, commonly known as the narrow shell orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this species the flower is green, white and brown with an inflated base, a narrow hood and the longest labellum of any Western Australian Pterostylis species.

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