Overview
The Dark Banded Greenhood (Pterostylis sanguinea) is an attractive and robust multi-flowered terrestrial greenhood orchid native to southern Australia. Unlike the predominantly solitary green blossoms of most greenhoods, this species produces a towering, crowded spike carrying up to a dozen glossy, nodding flowers heavily suffused with rich, blood-red and chocolate-brown tones. Thriving across diverse habitats from coastal scrub to dry inland mallee, it employs an irritable, trap-door labellum to orchestrate insect pollination.
Biology and Physical Characteristics
Pterostylis sanguinea produces a basal rosette of several ovate leaves that typically withers before flowering, replaced by stem-clasping, stem-borne leaves along the scape. In winter and spring (June to September), a sturdy, erect stem bears two to twelve densely packed, nodding flowers. The hooded galea is strongly striped and flushed with deep reddish-brown to dark chocolate hues with pale translucent windows. The lateral sepals are reflexed downwards, and the labellum is small, fleshy, and irritable, mounted on a flexible claw that triggers upon contact.
Behavior and Ecology
The pollination mechanism of Pterostylis sanguinea is a classic mechanical trap system. Tiny fungus gnats (Mycetophilidae) and sciarid flies are attracted to the blossom by subtle fungal scent mimicry. When a gnat lands on the raised labellum, the irritable hinge springs violently upward, trapping the insect inside the hollow floral column against the galea. As the gnat crawls frantically toward the light escaping through the translucent windows near the top, it is forced through a narrow exit chute where it picks up or deposits pollinia.
Conservation and Human Impact
Evaluated as Least Concern, the Dark Banded Greenhood is one of the hardiest and most widespread terrestrial orchids in southern Australia. It forms vigorous colonies on lateritic gravels, sandy heaths, and granite rock aprons across numerous national parks and reserves. Because it relies on healthy mycorrhizal fungal relationships and soil moisture during early winter, preserving natural woodland ground layers and minimizing weed encroachment are key management priorities.
Interesting Factoid
The specific epithet sanguinea comes from the Latin word for ‘bloody’ or ‘blood-red,’ highlighting the unusual, rich crimson-brown coloration that distinguishes this greenhood from its purely emerald relatives.
Last updated: October 2026