Synonyms for Helmet Orchid (same or very similar meaning)
WordNet sense 1 (any of numerous orchids of the genus Pterostylis having leaves in a basal rosette and green flowers often striped purple or brown or red with the dorsal sepal incurved to form a hood):
greenhoodWordNet sense 2 (any of several orchids of the genus Coryanthes having racemes of a few musky-scented waxy flowers with a helmet-shaped lip process):
helmetflowerFrom the ODE community, based on WordNetadd/edit